+publisher:"Clemson University" +contributor:("Thompson, Lonny")

Clemson University

1. Iyer, Vaibhav. ACOUSTIC SCATTERING AND RADIATION RESPONSE OF CIRCULAR HEXAGONAL AND AUXETIC HONEYCOMB SHELL STRUCTURES.

Degree: MS, Mechanical Engineering, 2014, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1912

► Sandwich panels with honeycomb cores are used in many engineering applications because of their high strength to weight ratio, vibration isolation and sound transmission… (more)

▼ Sandwich panels with honeycomb cores are used in many engineering applications because of their high strength to weight ratio, vibration isolation and sound transmission loss characteristics. Previous studies indicate that such sandwich structures with auxetic honeycomb cores (negative in-plane Poisson's ratio) can have a higher sound transmission loss compared to a regular hexagonal honeycomb core structure. In this study, sound scattering and acoustic radiation characteristics of sandwich structures with hexagonal and auxetic cores arranged in a circular pattern interacting with exterior acoustic domains of both air and water have been investigated using finite element analysis. A novel in-plane honeycomb geometry is developed which provides for a gradual decrease in radial cell size and whole number of circumferential cells to generate a uniform distribution of cells in the circular shell. Adding more circumferential cells, enables outer honeycomb edges to approach a circular arc and provides a comparison between the circular honeycomb and a solid elastic cylinder shell with the same mass. Natural frequencies of the different shell structures in-vacuo have been extracted in the analysis range of 0-2000 Hz. It is observed that auxetic honeycomb has lower natural frequencies compared to regular honeycomb for the same mass indicating that the auxetic is more flexible. The acoustic scattering and radiation performance in terms of target strength (TS) defined as the magnitude of reflected/scattered wave pressure relative to the magnitude of the incident plane wave pressure is measured both on the scattering surface and far-field at both the back and front scattering point were studied in both air and water. In the case of interaction with air in the exterior acoustic region, the radiation response shows prominent resonance peaks at the in-vacuo natural frequencies of the elastic structures as expected. Results show that there are significant differences in target strength between the auxetic and regular honeycomb and elastic solid circular shell structures studied, with relative TS performance between the different shells depending on the frequency of the incident wave and the acoustic domain used. Advisors/Committee Members: Thompson, Lonny L, Li , Gang, Summers , Joshua.

Subjects/Keywords: Cylindrical shell; Radiation; Scattering; Audio Arts and Acoustics; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Iyer, V. (2014). ACOUSTIC SCATTERING AND RADIATION RESPONSE OF CIRCULAR HEXAGONAL AND AUXETIC HONEYCOMB SHELL STRUCTURES. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1912

Chicago Manual of Style (16^th Edition):

Iyer, Vaibhav. “ACOUSTIC SCATTERING AND RADIATION RESPONSE OF CIRCULAR HEXAGONAL AND AUXETIC HONEYCOMB SHELL STRUCTURES.” 2014. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1912.

MLA Handbook (7^th Edition):

Iyer, Vaibhav. “ACOUSTIC SCATTERING AND RADIATION RESPONSE OF CIRCULAR HEXAGONAL AND AUXETIC HONEYCOMB SHELL STRUCTURES.” 2014. Web. 20 Jan 2021.

Vancouver:

Iyer V. ACOUSTIC SCATTERING AND RADIATION RESPONSE OF CIRCULAR HEXAGONAL AND AUXETIC HONEYCOMB SHELL STRUCTURES. [Internet] [Masters thesis]. Clemson University; 2014. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1912.

Council of Science Editors:

Iyer V. ACOUSTIC SCATTERING AND RADIATION RESPONSE OF CIRCULAR HEXAGONAL AND AUXETIC HONEYCOMB SHELL STRUCTURES. [Masters Thesis]. Clemson University; 2014. Available from: https://tigerprints.clemson.edu/all_theses/1912

Clemson University

2. Ranganathan, Shivraj. Effects of Iteration on Concept Development.

Degree: MS, Mechanical Engineering, 2013, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1778

► Iteration in the conceptual design stage is defined as repetition of design tasks to incorporate new information. A more concise definition of iteration relevant… (more)

▼ Iteration in the conceptual design stage is defined as repetition of design tasks to incorporate new information. A more concise definition of iteration relevant to this research would be the progression of design through different abstraction levels or design stages, defining and refining design solutions while progressing from initial concepts to a more detailed design. Although it is believed that iteration has a positive effect on the quality of ideas in the design process, this experimental study presents an opportunity to determine the effects of iteration on quality of concepts and the factors that lead to increased quality of concepts. The research presented in this thesis details two user studies that were conducted to determine and understand if iteration in the conceptual design stages promotes quality of design concepts. The first user study conducted in this paper involved twelve mechanical engineering graduate students where the participants were provided with a design problem and were asked to generate solutions for the design problem. In order to study iteration of design tasks in the conceptual design stages the participants were divided into three user groups with the first user group participating in a continuous ideation session and the second and the third user groups engaged in a iterative ideation session involving one and two iterations respectively. The user groups that engaged in an iterative ideation session followed the Gallery method of idea generation. The concepts generated by these students were evaluated in terms of quality and quantity metrics by two raters. Results from this study indicate that the quantity of ideas generated decreases with an increase in the number of iterations. A second user study was conducted to study effect of iteration of quality and quantity of concepts by using incubation as an ideation component. This study involved nine graduate level mechanical engineering students generating design solutions to a problem provided to them. The participants were divided into three user groups with the first user group participating in a continuous ideation session and the second and the third user groups engaged in an ideation session involving one and two design iterations respectively. The purpose of this study was to observe, record and analyze the design performance of the participants when iteration is explicitly performed in an unsupervised setting. The concepts generated by the participants were then evaluated from the perspective of `best' quality in addition to average quality of ideas from the session. The results from this user study indicated that the `best' quality of ideas at the participant level increases with an increase in the number of iterations. Consequently the number or the quantity of ideas decreases with an increase in the number of iterations resulting in a strain of convergent high quality design solutions. Our proposed model of creativity based on an iterative idea generation process suggests that as the number of iterations increases the… Advisors/Committee Members: Mocko, Gregory M, Fadel , Georges M, Thompson , Lonny L.

Subjects/Keywords: Conceptual Design; Creativity; Iteration; Metrics; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ranganathan, S. (2013). Effects of Iteration on Concept Development. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1778

Chicago Manual of Style (16^th Edition):

Ranganathan, Shivraj. “Effects of Iteration on Concept Development.” 2013. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1778.

MLA Handbook (7^th Edition):

Ranganathan, Shivraj. “Effects of Iteration on Concept Development.” 2013. Web. 20 Jan 2021.

Vancouver:

Ranganathan S. Effects of Iteration on Concept Development. [Internet] [Masters thesis]. Clemson University; 2013. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1778.

Council of Science Editors:

Ranganathan S. Effects of Iteration on Concept Development. [Masters Thesis]. Clemson University; 2013. Available from: https://tigerprints.clemson.edu/all_theses/1778

Clemson University

3. Adeshara, Jasmin. DESIGN OPTIMIZATION OF GEOMETRICAL PARAMETERS AND MATERIAL PROPERTIES OF VIBRATING BIMORPH CANTILEVER BEAMS WITH SOLID AND HONEYCOMB SUBSTRATES FOR MAXIMUM ENERGY HARVESTED.

Degree: MS, Mechanical Engineering, 2013, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1717

► The objective of this thesis is to maximize the energy harvested from a vibrating bimorph cantilever beam by optimizing the geometrical parameters and the… (more)

▼ The objective of this thesis is to maximize the energy harvested from a vibrating bimorph cantilever beam by optimizing the geometrical parameters and the material properties of the piezoelectric beam. A three-dimensional finite element (FEA) model is developed to design a vibrating bimorph cantilever beam for energy harvesting. The reference piezoelectric material used in the design is Lead Zirconate Titanate (PZT-5H) and the substrate sandwiched between the two piezoelectric plates is brass. Three types of models are analyzed and compared in this work by modifying the brass substrate geometry- a solid homogenous substrate, a regular honeycomb substrate and an auxetic honeycomb substrate. Complete transversely isotropic elastic and piezoelectric properties are assigned to the bimorph layers. A time harmonic pressure load is applied to the top surface of the beam that results in electrical-mechanical coupling by vibration. The electric potential on the surfaces of the bimorph piezoelectric beam is used to compute voltage generated. Also in this thesis, an automated design workflow has been set-up to solve an optimization problem by integrating ABAQUS 6.10, the commercial finite element package with the commercial optimization software package VisualDOC 7.1. The optimizer, Non-dominated Sorting Genetic Algorithm II (NSGAII), depends on the number of population, iterations, probability of cross over and mutations. The first objective of this work is to compare the finite element analysis results of the bimorph cantilever beams with these three substrates for similar loading and boundary conditions. The thickness of the substrates and the material properties are maintained equal for all three models. The second objective is to optimize the thicknesses of the PZT plates `tp' and the relative dielectric constant to maximize the power harvested (i.e. voltage output) for a given loading condition and plate dimensions (length and width). The constraint used for solving this non-linear multi-physics optimization problem is the ultimate tensile stress for the piezoelectric plates. The optimized parameters obtained from VisualDOC are verified using ABAQUS and the results are compared. Advisors/Committee Members: Thompson, Lonny L, Fadel , Georges M, Zhao , Huijuan.

Subjects/Keywords: Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Adeshara, J. (2013). DESIGN OPTIMIZATION OF GEOMETRICAL PARAMETERS AND MATERIAL PROPERTIES OF VIBRATING BIMORPH CANTILEVER BEAMS WITH SOLID AND HONEYCOMB SUBSTRATES FOR MAXIMUM ENERGY HARVESTED. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1717

Chicago Manual of Style (16^th Edition):

Adeshara, Jasmin. “DESIGN OPTIMIZATION OF GEOMETRICAL PARAMETERS AND MATERIAL PROPERTIES OF VIBRATING BIMORPH CANTILEVER BEAMS WITH SOLID AND HONEYCOMB SUBSTRATES FOR MAXIMUM ENERGY HARVESTED.” 2013. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1717.

MLA Handbook (7^th Edition):

Adeshara, Jasmin. “DESIGN OPTIMIZATION OF GEOMETRICAL PARAMETERS AND MATERIAL PROPERTIES OF VIBRATING BIMORPH CANTILEVER BEAMS WITH SOLID AND HONEYCOMB SUBSTRATES FOR MAXIMUM ENERGY HARVESTED.” 2013. Web. 20 Jan 2021.

Vancouver:

Adeshara J. DESIGN OPTIMIZATION OF GEOMETRICAL PARAMETERS AND MATERIAL PROPERTIES OF VIBRATING BIMORPH CANTILEVER BEAMS WITH SOLID AND HONEYCOMB SUBSTRATES FOR MAXIMUM ENERGY HARVESTED. [Internet] [Masters thesis]. Clemson University; 2013. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1717.

Council of Science Editors:

Adeshara J. DESIGN OPTIMIZATION OF GEOMETRICAL PARAMETERS AND MATERIAL PROPERTIES OF VIBRATING BIMORPH CANTILEVER BEAMS WITH SOLID AND HONEYCOMB SUBSTRATES FOR MAXIMUM ENERGY HARVESTED. [Masters Thesis]. Clemson University; 2013. Available from: https://tigerprints.clemson.edu/all_theses/1717

Clemson University

4. Fernandez, Luis. TOPOLOGY OPTIMIZATION USING A LEVEL SET PENALIZATION WITH CONSTRAINED TOPOLOGY FEATURES.

Degree: MS, Mechanical Engineering, 2013, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1700

► Topology optimization techniques have been applied to structural design problems in order to determine the best material distribution in a given domain. The topology… (more)

▼ Topology optimization techniques have been applied to structural design problems in order to determine the best material distribution in a given domain. The topology optimization problem is ill-posed because optimal designs tend to have infinite number of holes. In order to regularize this problem, a geometrical constraint, for instance the perimeter of the design (i.e., the measure of the boundary of the solid region, length in 2D problems or the surface area in 3D problems) is usually imposed. In this thesis, a novel methodology to solve the topology optimization problem with a constraint on the number of holes is proposed. Case studies are performed and numerical tests evaluated as a way to establish the efficacy and reliability of the proposed method. In the proposed topology optimization process, the material/void distribution evolves towards the optimum in an iterative process in which discretization is performed by finite elements and the material densities in each element are considered as the design variables. In this process, the material/void distribution is updated by a two-step procedure. In the first step, a temporary density function, ϕ*(x), is updated through the steepest descent direction. In the subsequent step, the temporary density function ϕ*(x) is used to model the next material/void distribution, χ*(x), by means of the level set concept. With this procedure, holes are easily created and quantified, material is conveniently added/removed. If the design space is reduced to the elements in the boundary, the topology optimization process turns into a shape optimization procedure in which the boundaries are allowed to move towards the optimal configuration. Thus, the methodology proposed in this work controls the number of holes in the optimal design by combining both topology and shape optimization. In order to evaluate the effectiveness of the proposed method, 2-D minimum compliance problems with volume constraints are solved and numerical tests performed. In addition, the method is capable of handling very general objective functions, and the sensitivities with respect to the design variables can be conveniently computed. Advisors/Committee Members: Fadel, Georges M, Thompson , Lonny, Qiao , Rui, Guarneri , Paolo.

Subjects/Keywords: holes; level set functions; shape optimization; topology optimization; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Fernandez, L. (2013). TOPOLOGY OPTIMIZATION USING A LEVEL SET PENALIZATION WITH CONSTRAINED TOPOLOGY FEATURES. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1700

Chicago Manual of Style (16^th Edition):

Fernandez, Luis. “TOPOLOGY OPTIMIZATION USING A LEVEL SET PENALIZATION WITH CONSTRAINED TOPOLOGY FEATURES.” 2013. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1700.

MLA Handbook (7^th Edition):

Fernandez, Luis. “TOPOLOGY OPTIMIZATION USING A LEVEL SET PENALIZATION WITH CONSTRAINED TOPOLOGY FEATURES.” 2013. Web. 20 Jan 2021.

Vancouver:

Fernandez L. TOPOLOGY OPTIMIZATION USING A LEVEL SET PENALIZATION WITH CONSTRAINED TOPOLOGY FEATURES. [Internet] [Masters thesis]. Clemson University; 2013. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1700.

Council of Science Editors:

Fernandez L. TOPOLOGY OPTIMIZATION USING A LEVEL SET PENALIZATION WITH CONSTRAINED TOPOLOGY FEATURES. [Masters Thesis]. Clemson University; 2013. Available from: https://tigerprints.clemson.edu/all_theses/1700

Clemson University

5. Galgalikar, Rohan. DESIGN AUTOMATION AND OPTIMIZATION OF HONEYCOMB STRUCTURES FOR MAXIMUM SOUND TRANSMISSION LOSS.

Degree: MS, Mechanical Engineering, 2012, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1514

► Cellular materials with macro effective properties defined by repeated meso-structures are increasingly replacing conventional homogeneous materials due to their high strength to weight ratio,… (more)

▼ Cellular materials with macro effective properties defined by repeated meso-structures are increasingly replacing conventional homogeneous materials due to their high strength to weight ratio, and controllable effective mechanical properties, such as negative Poisson's ratio and tailored orthotropic elastic properties. Honeycomb structures are a well-known cellular material that has been used extensively in aerospace and other industries where the premium on the weight reduction with high-strength is required. Common applications of honeycomb cellular structures are their use as the core material in sandwich plates and plates between two face sheets. Honeycomb structures are built from repetition of a common hexagonal unit cell tessellation defined by four independent geometric parameters; the hexagonal unit cell side lengths, h, and l, cell wall thickness, t and orientation of the angle between the cell walls . These parameters can be controlled to achieve desirable effective properties. Another important application of honeycomb sandwich structures is the ability to adjust the unit cell geometric parameters to increase the Sound Transmission Loss (STL); a metric for measurement of noise cancellation for acoustic waves passing though the panel structure, while maintaining a low mass, and controllable effective stiffness and strength properties. Previous research has been limited to parametric studies exploring the effect of change in a single unit cell parameter on the Sound Transmission Loss (STL). To obtain an optimal STL result and to determine sensitivities, the present work presents a novel technique to control all four of the unit cell parameters while maintaining constant overall dimensions and mass of the honeycomb sandwich plate. These two constraints are necessary to ascertain that the high STL occurs only due to the change in geometric properties of honeycomb unit cell, as the STL increases with increase in mass and change in overall dimensions. An optimization problem has been set-up with the design variables as hexagonal interior angle, number of unit cells in the horizontal direction, and number of unit cells in the vertical direction for a representative plate model with in-plane acoustic pressure wave transmission analysis. These variables indirectly control the other unit cell lengths and cell-wall thickness parameters while satisfying the aforementioned constraints. All three of the design variables are restricted to integers to ensure the resulting geometry is regular and manufacturable. The STL response is optimized over a frequency range of 200-400 Hz, within a typical resonance region of the frequency response function. The goal of the optimization is to maximize the area under the STL curve over the frequency range of interest, with constraints on fixed mass and overall plate dimensions. The optimization process required a complete design automation workflow of geometry creation based on changes in number of cells, constraints on overall dimensions and mass, output… Advisors/Committee Members: Thompson, Lonny L, Summers, Joshua D, Fadel, Georges M.

Subjects/Keywords: Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Galgalikar, R. (2012). DESIGN AUTOMATION AND OPTIMIZATION OF HONEYCOMB STRUCTURES FOR MAXIMUM SOUND TRANSMISSION LOSS. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1514

Chicago Manual of Style (16^th Edition):

Galgalikar, Rohan. “DESIGN AUTOMATION AND OPTIMIZATION OF HONEYCOMB STRUCTURES FOR MAXIMUM SOUND TRANSMISSION LOSS.” 2012. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1514.

MLA Handbook (7^th Edition):

Galgalikar, Rohan. “DESIGN AUTOMATION AND OPTIMIZATION OF HONEYCOMB STRUCTURES FOR MAXIMUM SOUND TRANSMISSION LOSS.” 2012. Web. 20 Jan 2021.

Vancouver:

Galgalikar R. DESIGN AUTOMATION AND OPTIMIZATION OF HONEYCOMB STRUCTURES FOR MAXIMUM SOUND TRANSMISSION LOSS. [Internet] [Masters thesis]. Clemson University; 2012. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1514.

Council of Science Editors:

Galgalikar R. DESIGN AUTOMATION AND OPTIMIZATION OF HONEYCOMB STRUCTURES FOR MAXIMUM SOUND TRANSMISSION LOSS. [Masters Thesis]. Clemson University; 2012. Available from: https://tigerprints.clemson.edu/all_theses/1514

Clemson University

6. Gong, Xiao. VIBRATION AND ACOUSTIC PERFORMANCE OF IN-PLANE HONEYCOMB SANDWICH PANELS.

Degree: MS, Mechanical Engineering, 2012, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1483

► Sandwich panel structures constructed with cellular honeycomb cores allow for control of acoustic performance due to their ability to optimize effective orthotropic material properties… (more)

▼ Sandwich panel structures constructed with cellular honeycomb cores allow for control of acoustic performance due to their ability to optimize effective orthotropic material properties with changes in cell geometry. By modification of topology and geometric parameters of a unit cell, desirable effective properties can be obtained and used to design lightweight structures with reduced vibration and increased sound transmission loss properties. Thus investigating the relation between the geometric configuration of the honeycomb core and vibration and acoustic behavior is important to optimize design of sandwich panels. In this work, a finite element model is developed in MATLAB to evaluate the resonance frequencies, vibration frequency response and structural behavior of general honeycomb sandwich panels undergoing in-plane loading. Bernoulli-Euler beam element stiffness and mass matrices are computed with coordinate transformations to assemble for two-dimensional frame dynamic analysis. The developed MATLAB finite element program is written to allow the user to specify any unit cell geometry together with the number of repeated cells along the longitudinal and transverse direction of a honeycomb sandwich panel. This automation allows for rapid studies of the effects of the cell geometry and number of cells for optimization and parametric studies. In addition, the user can specify the size of elements for cell length subdivision to ensure mesh convergence analysis. The developed MATLAB code was verified by comparing dynamic results to finite element models created using the commercial software ABAQUS using both cubic Bernoulli-Euler and quadratic Timoshenko beam elements. Natural vibration frequencies of the structure and vibration amplitude frequency response for honeycomb structures are computed between 1~1000 Hz, corresponding to low to medium frequency ranges. In addition, the ABAQUS finite element model is used to simulate the acoustic behavior of the sandwich panel mounted in a rigid baffle resulting from an incident plane pressure wave. This required the coupling of an acoustic finite element model tied to the sandwich panel model to model sound radiation from the vibrating panel. To model the infinite acoustic region on one side of the sandwich panel, the acoustic finite element mesh is truncated using a founded ellipse non-reflecting boundary condition (NRBC). Previous studies used a circular nonreflecting boundary condition. The use of an ellipse for the NRBC allows for a reduced size computational region surrounding the elongated sandwich panel structure. The accuracy of the NRBC's was also studied as a function of distance from the vibrating panel source. Various core configurations of different geometric and effective material properties for regular and auxetic honeycomb cell geometries with two different orthogonal orientations were studied. Constant mass property is applied for sandwich panels with different number of longitudinal and transverse cell numbers to identify the effects of… Advisors/Committee Members: Thompson, Lonny L, Li , Gang, Daqaq , Mohammed.

Subjects/Keywords: Finite element; Honeycomb; sandwich panel; sound transmission loss; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Gong, X. (2012). VIBRATION AND ACOUSTIC PERFORMANCE OF IN-PLANE HONEYCOMB SANDWICH PANELS. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1483

Chicago Manual of Style (16^th Edition):

Gong, Xiao. “VIBRATION AND ACOUSTIC PERFORMANCE OF IN-PLANE HONEYCOMB SANDWICH PANELS.” 2012. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1483.

MLA Handbook (7^th Edition):

Gong, Xiao. “VIBRATION AND ACOUSTIC PERFORMANCE OF IN-PLANE HONEYCOMB SANDWICH PANELS.” 2012. Web. 20 Jan 2021.

Vancouver:

Gong X. VIBRATION AND ACOUSTIC PERFORMANCE OF IN-PLANE HONEYCOMB SANDWICH PANELS. [Internet] [Masters thesis]. Clemson University; 2012. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1483.

Council of Science Editors:

Gong X. VIBRATION AND ACOUSTIC PERFORMANCE OF IN-PLANE HONEYCOMB SANDWICH PANELS. [Masters Thesis]. Clemson University; 2012. Available from: https://tigerprints.clemson.edu/all_theses/1483

Clemson University

7. Griese, David. Finite Element Modeling and Design of Honeycomb Sandwich Panels for Acoustic Performance.

Degree: MS, Mechanical Engineering, 2012, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1299

► Honeycomb cellular metamaterial structures offer many distinct advantages over homogenous materials because their effective material properties depend on both their constituent material properties and… (more)

Subjects/Keywords: Acoustics; Design; Finite Elements; Honeycomb; Metamaterial; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Griese, D. (2012). Finite Element Modeling and Design of Honeycomb Sandwich Panels for Acoustic Performance. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1299

Chicago Manual of Style (16^th Edition):

Griese, David. “Finite Element Modeling and Design of Honeycomb Sandwich Panels for Acoustic Performance.” 2012. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1299.

MLA Handbook (7^th Edition):

Griese, David. “Finite Element Modeling and Design of Honeycomb Sandwich Panels for Acoustic Performance.” 2012. Web. 20 Jan 2021.

Vancouver:

Griese D. Finite Element Modeling and Design of Honeycomb Sandwich Panels for Acoustic Performance. [Internet] [Masters thesis]. Clemson University; 2012. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1299.

Council of Science Editors:

Griese D. Finite Element Modeling and Design of Honeycomb Sandwich Panels for Acoustic Performance. [Masters Thesis]. Clemson University; 2012. Available from: https://tigerprints.clemson.edu/all_theses/1299

Clemson University

8. He, Lei. Composite Sandwich Structures with Honeycomb Core subjected to Impact.

Degree: MS, Mechanical Engineering, 2012, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1547

► Composite sandwich structures constructed with honeycomb core can be an effective means of absorbing impact in many engineer applications. Conventional hexagonal honeycomb exhibit an… (more)

▼ Composite sandwich structures constructed with honeycomb core can be an effective means of absorbing impact in many engineer applications. Conventional hexagonal honeycomb exhibit an effective positive Poisson's ratio, are commonly employed due to their lightweight and high axial stiffness properties. In contrast, auxetic honeycombs offer high in-plane shear stiffness, and exhibit negative Poisson's ratios with lateral extension, instead of contraction, when stretched axially. In this study, the dynamic response of an aluminum composite panel with a honeycomb core constrained within two thin face sheets is investigated undergoing impact with a rigid ball. The finite element models used to simulate impact of the rigid ball with the honeycomb composite panel are solved using a nonlinear explicit dynamic analysis procedure including large deformation in ABAQUS, a commercial software package. This approach enables the cost-effective analysis, accurate estimation of the impact, and further understanding of the parameters that influence the complex response. The rebound velocity and kinetic energy time history of the rigid ball, together with the kinetic and strain energies, and displacement and velocity for the elastic structure during impact and after separation of the impacting bodies are presented to show the effect of different velocity magnitudes of the impacting ball and comparisons with regular and auxetic honeycomb cell geometries. Additionally, the effects of various impacting velocities and honeycomb geometries are compared for impact in two perpendicular in-plane directions, and from out-of-plane impact. Using the results of the incoming and rebound velocity of the ball, as well as the velocity of the point of contact on the structure at separation, and effective coefficient of restitution (COR) for the honeycomb sandwich structure is calculated and compared. Other measures include the ratio of incoming to outgoing fall velocities and ratio of incoming to outgoing kinetic energies. Results show that the increase of the impacting velocity increases both the kinetic energy and strain energy absorbed in the structure. Results also showed that for both in-plane and out-of-plane impacts, the regular honeycomb structure absorbed more energy compared to the auxetic structure. In addition, according to the results of the COR, impact with the auxetic model shows higher elastic rebound than the regular model. Advisors/Committee Members: Thompson, Lonny, Li , Gang, Daqaq , Mohammed.

Subjects/Keywords: Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

He, L. (2012). Composite Sandwich Structures with Honeycomb Core subjected to Impact. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1547

Chicago Manual of Style (16^th Edition):

He, Lei. “Composite Sandwich Structures with Honeycomb Core subjected to Impact.” 2012. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1547.

MLA Handbook (7^th Edition):

He, Lei. “Composite Sandwich Structures with Honeycomb Core subjected to Impact.” 2012. Web. 20 Jan 2021.

Vancouver:

He L. Composite Sandwich Structures with Honeycomb Core subjected to Impact. [Internet] [Masters thesis]. Clemson University; 2012. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1547.

Council of Science Editors:

He L. Composite Sandwich Structures with Honeycomb Core subjected to Impact. [Masters Thesis]. Clemson University; 2012. Available from: https://tigerprints.clemson.edu/all_theses/1547

Clemson University

9. Subrahmanian, Ramaswami. Applying Chaotic Advection to Rheology: an In Situ Structuring Rheometer.

Degree: PhD, Mechanical Engineering, 2012, Clemson University

URL: https://tigerprints.clemson.edu/all_dissertations/791

► A prototype In Situ Structuring Rheometer (ISSR) was designed and implemented to study changes in shear viscosity of polymer blends and composites while processing them… (more)

▼ A prototype In Situ Structuring Rheometer (ISSR) was designed and implemented to study changes in shear viscosity of polymer blends and composites while processing them in such a way as to control the evolution of microstructure. The ISSR is based on a regime of fluid mechanics known as chaotic advection, in which simple time-periodic flow fields can cause fluid particles to move chaotically. Chaotic advection is also the basis of Smart Blending, a technology employed to process polymer blends having a variety of morphologies at a fixed composition, and polymer composites in which the additives have been arranged into layered structures or networks. Smart Blending has been implemented as batch devices or continuous flow devices, with a device of the former type providing the basis for the ISSR. Designed as a test cell to be fitted into a commercial instrument so as to leverage its measurement capability, the core of the ISSR is a cylindrical blending cavity the end surfaces of which are formed by rotatable disks which induce stirring. While the upper disk is an attachment for the commercial instrument, the lower disk has an independent drive system. The ISSR also includes a heating chamber, temperature control systems and a purge gas system. Alternate counter-rotation of the disks through an appropriate displacement leads to a chaotic flow. The design of the ISSR and experiments conducted using it were guided by modeling. The result is that even as the microstructure in the sample is being controllably formed, the shear viscosity is measured each time the upper disk rotates. In contrast, conventional rheometry using a parallel-plate or cone-plate test cell involves mixing materials as melts beforehand, with a polymer blend usually having a droplet morphology and a composite usually having the additive randomly dispersed throughout the polymer matrix. Three types of systems were processed and studied using the ISSR. At least three samples of each system were processed to different extents, cryogenically fractured and examined using scanning electron microscopy (SEM). By so doing, the trends in viscosity were related to progressive structure development, which is the controlled evolution and retention of particular blend and composite morphologies, as has been documented in previous chaotic advection blending studies. The first system was a compatible blend of low density polyethylene (LDPE) and high density polyethylene (HDPE), for which the viscosity initially rose and eventually reached a plateau, which was consistent with a model that showed no change in viscosity with the number of layers. Blend samples at different stages of processing showed the initial formation of layers and the development of nanoscale features as these layers refined. The second system was a composite of linear low density polyethylene (LLDPE) and carbon black (CB), for which the shear viscosity slowly decreased with continued processing. Micrographs indicated that the carbon black initially… Advisors/Committee Members: Zumbrunnen, David A, Grujicic , Mica, Li , Gang, Thompson , Lonny.

Subjects/Keywords: Blends; Chaotic advection; In Situ Structuring; Rheology; Rheometer; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Subrahmanian, R. (2012). Applying Chaotic Advection to Rheology: an In Situ Structuring Rheometer. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/791

Chicago Manual of Style (16^th Edition):

Subrahmanian, Ramaswami. “Applying Chaotic Advection to Rheology: an In Situ Structuring Rheometer.” 2012. Doctoral Dissertation, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_dissertations/791.

MLA Handbook (7^th Edition):

Subrahmanian, Ramaswami. “Applying Chaotic Advection to Rheology: an In Situ Structuring Rheometer.” 2012. Web. 20 Jan 2021.

Vancouver:

Subrahmanian R. Applying Chaotic Advection to Rheology: an In Situ Structuring Rheometer. [Internet] [Doctoral dissertation]. Clemson University; 2012. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/791.

Council of Science Editors:

Subrahmanian R. Applying Chaotic Advection to Rheology: an In Situ Structuring Rheometer. [Doctoral Dissertation]. Clemson University; 2012. Available from: https://tigerprints.clemson.edu/all_dissertations/791

Clemson University

10. Hegenderfer, Joshua. Resource Allocation Framework: Validation of Numerical Models of Complex Engineering Systems against Physical Experiments.

Degree: PhD, Civil Engineering, 2012, Clemson University

URL: https://tigerprints.clemson.edu/all_dissertations/960

► An increasing reliance on complex numerical simulations for high consequence decision making is the motivation for experiment-based validation and uncertainty quantification to assess, and when… (more)

▼ An increasing reliance on complex numerical simulations for high consequence decision making is the motivation for experiment-based validation and uncertainty quantification to assess, and when needed, to improve the predictive capabilities of numerical models. Uncertainties and biases in model predictions can be reduced by taking two distinct actions: (i) increasing the number of experiments in the model calibration process, and/or (ii) improving the physics sophistication of the numerical model. Therefore, decision makers must select between further code development and experimentation while allocating the finite amount of available resources. This dissertation presents a novel framework to assist in this selection between experimentation and code development for model validation strictly from the perspective of predictive capability. The reduction and convergence of discrepancy bias between model prediction and observation, computed using a suitable convergence metric, play a key role in the conceptual formulation of the framework. The proposed framework is demonstrated using two non-trivial case study applications on the Preston-Tonks-Wallace (PTW) code, which is a continuum-based plasticity approach to modeling metals, and the ViscoPlastic Self-Consistent (VPSC) code which is a mesoscopic plasticity approach to modeling crystalline materials. Results show that the developed resource allocation framework is effective and efficient in path selection (i.e. experimentation and/or code development) resulting in a reduction in both model uncertainties and discrepancy bias. The framework developed herein goes beyond path selection in the validation of numerical models by providing a methodology for the prioritization of optimal experimental settings and an algorithm for prioritization of code development. If the path selection algorithm selects the experimental path, optimal selection of the settings at which these physical experiments are conducted as well as the sequence of these experiments is vital to maximize the gain in predictive capability of a model. The Batch Sequential Design (BSD) is a methodology utilized in this work to achieve the goal of selecting the optimal experimental settings. A new BSD selection criterion, Coverage Augmented Expected Improvement for Predictive Stability (C-EIPS), is developed to minimize the maximum reduction in the model discrepancy bias and coverage of the experiments within the domain of applicability. The functional form of the new criterion, C-EIPS, is demonstrated to outperform its predecessor, the EIPS criterion, and the distance-based criterion when discrepancy bias is high and coverage is low, while exhibiting a comparable performance to the distance-based criterion in efficiently maximizing the predictive capability of the VPSC model as discrepancy decreases and coverage increases. If the path selection algorithm selects the code development path,… Advisors/Committee Members: Atamturktur, Sezer, Juang , Hsein, Khan , Abdul, Thompson , Lonny.

Subjects/Keywords: Bayesian calibration; code prioritization; experimental design; model validation; uncertainty quantification; Civil Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Hegenderfer, J. (2012). Resource Allocation Framework: Validation of Numerical Models of Complex Engineering Systems against Physical Experiments. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/960

Chicago Manual of Style (16^th Edition):

Hegenderfer, Joshua. “Resource Allocation Framework: Validation of Numerical Models of Complex Engineering Systems against Physical Experiments.” 2012. Doctoral Dissertation, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_dissertations/960.

MLA Handbook (7^th Edition):

Hegenderfer, Joshua. “Resource Allocation Framework: Validation of Numerical Models of Complex Engineering Systems against Physical Experiments.” 2012. Web. 20 Jan 2021.

Vancouver:

Hegenderfer J. Resource Allocation Framework: Validation of Numerical Models of Complex Engineering Systems against Physical Experiments. [Internet] [Doctoral dissertation]. Clemson University; 2012. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/960.

Council of Science Editors:

Hegenderfer J. Resource Allocation Framework: Validation of Numerical Models of Complex Engineering Systems against Physical Experiments. [Doctoral Dissertation]. Clemson University; 2012. Available from: https://tigerprints.clemson.edu/all_dissertations/960

Clemson University

11. Gandhi, Ninad. FINITE ELEMENT ANALYSIS OF EFFECTIVE MECHANICAL PROPERTIES OF HIERARCHICAL HONEYCOMB STRUCTURES.

Degree: MS, Mechanical Engineering, 2015, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/2216

► Honeycomb structures are widely used in engineering applications mainly due to their high strength to weight ratio. By changing the base material and geometry of… (more)

▼ Honeycomb structures are widely used in engineering applications mainly due to their high strength to weight ratio. By changing the base material and geometry of the repeating unit cell structure, target effective properties can be achieved. Hierarchical honeycomb structures are known to have enhanced mechanical properties when compared to regular honeycomb structures. Therefore, it is important to understand and quantify the mechanical properties and the variation of these properties with the presence of hierarchy. This investigation builds upon prior work and considers the mechanical properties of two dimensional hierarchical honeycomb structures. Previous research of hierarchical honeycomb structures studied replacing the homogeneous cell walls with truss lattices, or by replacing the cell walls by composite layers. Another hierarchy was examined by replacing the vertices of hexagon by smaller hexagons. However, in contrast to these previous studies, reiterated hierarchy is studied in this work, where a first order hierarchy structure is created by placing smaller honeycombs inside the conventional honeycombs such that midpoints of edges of the base level-0 honeycomb are shared vertices of the smaller level-1 honeycomb. In this work, the in-plane effective mechanical properties of these reiterated hierarchical honeycomb structures are studied with both regular and auxetic honeycombs. Effective elastic moduli and Poisson's ratio properties are determined and compared for a range of different cell wall thickness ratios between the base level-0 and smaller level-1 hierarchy. For comparisons, the mass was kept constant in all cases. Given the total mass and thickness ratio of the level-0 to level-1 hierarchy, the mass distribution is varied. The mechanical properties are determined from finite element analysis of a patch of honeycombs in both uni-axial tension and shear loading conditions. By changing the thickness ratio of level-0 to level-1 hierarchy, a nonlinear variation in mechanical properties is observed showing maximum and minimum values at specific ratios. From the results of first order regular hierarchical honeycomb structures, it can be said that for the same mass, the effective Young's modulus for thickness ratio of 0.1 between level-0 divided by level-1 is maximum and is about 1.45 times that of the zeroth order. Maximum effective shear modulus occurs for the special case with thickness ratio of zero, corresponding to a special level-1 honeycomb structure with the level-0 structure removed, and is 1.57 times that of the zeroth order. From the results of first order auxetic hierarchical honeycomb structures, it can be said that the effective relative Young's modulus, and shear modulus of first order is higher for any thickness ratio than that of the zeroth order auxetic honeycomb structure of the same mass. The maximum effective Young's modulus occurs for thickness ratio 9 and is about 2.8 times that of the zeroth order. The maximum effective shear modulus of first order structure… Advisors/Committee Members: Thompson, Lonny L, Summers, Joshua D, Li, Gang.

Subjects/Keywords: Auxetic hierarchical honeycomb structures; Effective mechanical properties of honeycomb structures; Finite element analysis; Hierarchical honeycomb structures; Honeycomb structures; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Gandhi, N. (2015). FINITE ELEMENT ANALYSIS OF EFFECTIVE MECHANICAL PROPERTIES OF HIERARCHICAL HONEYCOMB STRUCTURES. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/2216

Chicago Manual of Style (16^th Edition):

Gandhi, Ninad. “FINITE ELEMENT ANALYSIS OF EFFECTIVE MECHANICAL PROPERTIES OF HIERARCHICAL HONEYCOMB STRUCTURES.” 2015. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/2216.

MLA Handbook (7^th Edition):

Gandhi, Ninad. “FINITE ELEMENT ANALYSIS OF EFFECTIVE MECHANICAL PROPERTIES OF HIERARCHICAL HONEYCOMB STRUCTURES.” 2015. Web. 20 Jan 2021.

Vancouver:

Gandhi N. FINITE ELEMENT ANALYSIS OF EFFECTIVE MECHANICAL PROPERTIES OF HIERARCHICAL HONEYCOMB STRUCTURES. [Internet] [Masters thesis]. Clemson University; 2015. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/2216.

Council of Science Editors:

Gandhi N. FINITE ELEMENT ANALYSIS OF EFFECTIVE MECHANICAL PROPERTIES OF HIERARCHICAL HONEYCOMB STRUCTURES. [Masters Thesis]. Clemson University; 2015. Available from: https://tigerprints.clemson.edu/all_theses/2216

Clemson University

12. Seera, Nikhil. Viscoelastic Damping of Hexagonal Honeycomb Sandwich Panels.

Degree: MS, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1217

► Composite sandwich structures with a viscoelastic core material constrained between thin stiff face sheets are an effective means of damping in engineering applications. Damping introduces… (more)

▼ Composite sandwich structures with a viscoelastic core material constrained between thin stiff face sheets are an effective means of damping in engineering applications. Damping introduces energy dissipation which helps control vibration amplitudes. Conventional Hexagonal honeycombs are often referred to as regular honeycombs and are defined by cellular geometry with effective positive Poisson's ratio. Regular honeycombs are commonly used for the cores of sandwich plates because of their low density and high stiffness properties. Honeycombs with negative in-plane Poisson's ratio are known as Auxetic honeycombs and offer enhancement of mechanical properties such as impact absorption, damage resistance, when compared to regular honeycombs. In this study the modal vibration and damping capabilities of honeycomb sandwich plates with viscoelastic core are analyzed using a finite element model developed in ABAQUS. The viscoelastic material used for the base material of the honeycomb core is defined using a Prony series corresponding to the generalized Maxwell model. Damping loss factors are calculated from the ratio of energy dissipation over elastic strain energy for both a quasi-static analysis with a sinusoidal pressure load, and an implicit dynamic analysis with instantaneous pressure load. Additionally loss factors are calculated using a direct steady-state frequency response analysis, using half-power bandwidth method. Comparisons are made between regular and two configurations of auxetic honeycomb. The first auxetic honeycomb (Auxetic-I) considered has the same extensional in-plane effective moduli as regular honeycomb. In the other auxetic honeycomb, (Auxetic-II), the mass is the same as that of regular honeycombs. In addition, comparisons are made between in-plane and out-of-plane loading. Results showed that in the frequency domain, for both in-plane and out-of-plane loading honeycomb sandwich plates with both the Auxetic configurations show higher damping than the regular counterpart, and also shifts the natural frequencies to lower values. Results also show that for both regular and auxetic with in-plane loading display higher loss factors compared to out-of -plane loading. In the time domain, when a stiffer viscoelastic material is assigned to the core, Auxetic honeycomb showed higher loss factors compared to Regular. Whereas when softer viscoelastic moduli is defined, regular showed higher loss factors. Advisors/Committee Members: Thompson, Lonny L, Joseph , Paul F, Ju , Jaehyung.

Subjects/Keywords: Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Seera, N. (2011). Viscoelastic Damping of Hexagonal Honeycomb Sandwich Panels. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1217

Chicago Manual of Style (16^th Edition):

Seera, Nikhil. “Viscoelastic Damping of Hexagonal Honeycomb Sandwich Panels.” 2011. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1217.

MLA Handbook (7^th Edition):

Seera, Nikhil. “Viscoelastic Damping of Hexagonal Honeycomb Sandwich Panels.” 2011. Web. 20 Jan 2021.

Vancouver:

Seera N. Viscoelastic Damping of Hexagonal Honeycomb Sandwich Panels. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1217.

Council of Science Editors:

Seera N. Viscoelastic Damping of Hexagonal Honeycomb Sandwich Panels. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1217

Clemson University

13. Shan, Nan. ANALYTICAL SOLUTIONS USING HIGH ORDER COMPOSITE LAMINATE THEORY FOR HONEYCOMB SANDWICH PLATES WITH VISCOELASTIC FREQUENCY DEPENDENT DAMPING.

Degree: MS, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1213

► Analytical methods allow parametric changes in geometric and material properties of a honeycomb sandwich plate for studies of stiffness, mass, and damping characteristics with low… (more)

▼ Analytical methods allow parametric changes in geometric and material properties of a honeycomb sandwich plate for studies of stiffness, mass, and damping characteristics with low computational cost. However, studies based on analytical methods are still limited with frequency independent damping models. Specifically, previous analytical models have not consider the frequency dependent damping for viscoelastic honeycomb core sandwich composites, while some work has been done on studying the honeycomb sandwich plate using finite element method, which can be computationally expensive for multiple parameter studies. Therefore, in this work, the honeycomb sandwich plate is studied analytically based on the cellular material theory, together with composite laminate theory. In initial analytical studies, first-order shear deformation theory (FSDT) is used for symmetric honeycomb sandwich plate in order to capture important transverse shear effects in the core. In order to obtain a frequency response which includes frequency dependent viscoelastic damping properties, the study is based on a time harmonic analysis of the sandwich plate in the frequency domain. Two materials are compared for the core; aluminum and polycarbonate. For the aluminum honeycomb core, frequency independent damping is included and results compared with the results of different damping ratios. For the polycarbonate honeycomb core, the viscoelastic behavior is modeled using the generalized Maxwell damping model expressed in terms of the Prony series. The study begins with a simplified case of a simply supported honeycomb sandwich plate subject to a uniform distributed transverse time harmonic loading, which has infinite length such that the deformation in the width direction is independent of the length. The undamped natural frequencies are also derived analytically based on the free vibration problem and compared to the damped resonance frequencies in the frequency response of the plate. Comparisons are made between regular and two types of auxetic honeycomb cores. Regular honeycomb is defined by cellular geometry with effective Poisson's ratio of approximately one, whereas auxetic honeycomb has negative Poisson's ratio. Both regular and auxetic have special orthotropic properties. The case study is then generalized to a simply-supported sandwich honeycomb plate for a two dimensional problem. The response of the sandwich plate with regular honeycomb core is then compared with the responses of the two types of auxetic cores. Results for frequency response show shifts in resonance frequencies due to differences in stiffness and mass of the sandwich plate with different cores. Results from a composite sandwich plate finite element model using ANSYS with effective honeycomb core orthotropic properties was used to validate the analytical models in the case of no damping. A refined higher order shear deformation theory (RSDT), based on a piecewise kinematic axial displacement component assumption, for… Advisors/Committee Members: Thompson, Lonny, Daqaq , Mohammed, Ju , Jaehyung.

Subjects/Keywords: ANSYS; Frequency dependent; Honeycomb sandwich plate; Time harmonic; Viscoelastic material; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Shan, N. (2011). ANALYTICAL SOLUTIONS USING HIGH ORDER COMPOSITE LAMINATE THEORY FOR HONEYCOMB SANDWICH PLATES WITH VISCOELASTIC FREQUENCY DEPENDENT DAMPING. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1213

Chicago Manual of Style (16^th Edition):

Shan, Nan. “ANALYTICAL SOLUTIONS USING HIGH ORDER COMPOSITE LAMINATE THEORY FOR HONEYCOMB SANDWICH PLATES WITH VISCOELASTIC FREQUENCY DEPENDENT DAMPING.” 2011. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1213.

MLA Handbook (7^th Edition):

Shan, Nan. “ANALYTICAL SOLUTIONS USING HIGH ORDER COMPOSITE LAMINATE THEORY FOR HONEYCOMB SANDWICH PLATES WITH VISCOELASTIC FREQUENCY DEPENDENT DAMPING.” 2011. Web. 20 Jan 2021.

Vancouver:

Shan N. ANALYTICAL SOLUTIONS USING HIGH ORDER COMPOSITE LAMINATE THEORY FOR HONEYCOMB SANDWICH PLATES WITH VISCOELASTIC FREQUENCY DEPENDENT DAMPING. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1213.

Council of Science Editors:

Shan N. ANALYTICAL SOLUTIONS USING HIGH ORDER COMPOSITE LAMINATE THEORY FOR HONEYCOMB SANDWICH PLATES WITH VISCOELASTIC FREQUENCY DEPENDENT DAMPING. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1213

Clemson University

14. Telukunta, Rohit. CONSTRAINED LAYER DAMPING OF HONEYCOMB COMPOSITE STRUCTURES.

Degree: MS, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1162

► Composite sandwich structures have replaced homogenous dense solids in many applications due to their advantages of high stiffness to weight ratio, and higher damping characteristics.… (more)

▼ Composite sandwich structures have replaced homogenous dense solids in many applications due to their advantages of high stiffness to weight ratio, and higher damping characteristics. Higher damping in engineering applications is desirable to reduce structural vibrations. The application of a viscoelastic layer between two thin face sheets gives rise to the concept of constrained layer damping which is an effective technique to achieve increased damping in engineering applications. Honeycomb cellular structures are often used for the core in sandwich construction because of their low density and high stiffness properties. Regular honeycombs are defined by conventional hexagonal geometry, which gives rise to effective transversely isotropic properties. Auxetic honeycombs have cellular geometry defined such that their effective Poisson's ratio is negative, and have potential for increased shear modulus and nonconventional design compared to their regular counterparts. In this study, the damping nature of auxetic and regular honeycombs cores within a sandwich plate structure with equal mass density is studied using finite element analysis. A new concept of constrained layer damping is introduced within the honeycomb cell walls, making the honeycomb core, itself, a composite structure. By introducing the composite honeycomb core between two thin face sheets in the macro sandwich structure, further increases in damping can be achieved. The thickness of the constraining layers is defined such that the effective stiffness is increased for the same mass of a sandwich plate with homogeneous honeycomb core. Comparisons are made for both quasi-static cyclic loading and dynamic analysis subjected to impact loads. The amplitude of loading is defined at a level such that the yield stress within the base materials is not exceeded. Dissipation energy at the end of the loading step in the finite element analysis is used to quantify the structural loss factor. Results show higher damping is achieved with the novel concept of constrained layer viscoelastic damping in honeycomb cell walls. In the case of out-of-plane loading direction, sandwich plates with composite auxetic honeycomb core gives higher damping over homogeneous honeycomb core sandwich plates and its regular honeycomb counter parts. However, when loaded in the in-plane direction, a condition was found where sandwich plates with homogenous auxetic honeycomb core gave higher damping than with a composite core and its regular counter parts, suggesting that further development is needed to optimize the relative thicknesses of the constraining layer in the honeycomb cell walls. Advisors/Committee Members: THOMPSON, LONNY L, LI , GANG, FADEL , GEORGES M.

Subjects/Keywords: Composite; Constrained Layer Damping; Damping; Honeycomb; Loss factor; Sandwich plates; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Telukunta, R. (2011). CONSTRAINED LAYER DAMPING OF HONEYCOMB COMPOSITE STRUCTURES. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1162

Chicago Manual of Style (16^th Edition):

Telukunta, Rohit. “CONSTRAINED LAYER DAMPING OF HONEYCOMB COMPOSITE STRUCTURES.” 2011. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1162.

MLA Handbook (7^th Edition):

Telukunta, Rohit. “CONSTRAINED LAYER DAMPING OF HONEYCOMB COMPOSITE STRUCTURES.” 2011. Web. 20 Jan 2021.

Vancouver:

Telukunta R. CONSTRAINED LAYER DAMPING OF HONEYCOMB COMPOSITE STRUCTURES. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1162.

Council of Science Editors:

Telukunta R. CONSTRAINED LAYER DAMPING OF HONEYCOMB COMPOSITE STRUCTURES. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1162

Clemson University

15. Annapaneni, Puroorava. MOLECULAR DYNAMICS STUDY OF PARTICLE IMPACT INDUCED BOND BREAKING OF SINGLE-WALLED CARBON NANOTUBES AND QUALITY FACTORS OF NANOCOMPOSITE STRUCTURES.

Degree: MS, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1163

► Part A Injection of particles to the side wall of single-walled carbon nanotubes (SWCNT) has been employed for doping and storage of particles on SWCNTs.… (more)

▼ Part A Injection of particles to the side wall of single-walled carbon nanotubes (SWCNT) has been employed for doping and storage of particles on SWCNTs. In addition, particle bombardment can be used to cut and modify graphene structures. While the collision of hydrogen atoms with SWCNTs has been extensively studied, collision dynamic behavior of heavy particles with SWCNTs has not been well understood. To facilitate a better understanding of the particle-SWCNT collision process, in this work, we study the impact of five noble gas atoms (He, Ne, Ar, Kr, Xe) with SWCNTs and investigate particle impact induced CNT bond breaking phenomena. Simulation results include the bond-breaking kinetic energy ranges of the incident atoms with reflection and penetration after the collision. Effect of chirality, boundary and strain conditions of the SWCNTs and energy exchange between the incident atoms and carbon atoms of SWCNT are investigated. Simulation results show that, except for very small SWCNTs (diameter < 0.5 nm), the minimum bond-breaking energy of the incident atom is independent of the chirality/diameter and boundary conditions of the SWCNT. However, the incident atom mass as well as strain conditions of the SWCNT plays an important role in the minimum bond-breaking energy, collision behavior and energy loss of the incident atom. Part B Nanocomposite materials are increasingly used in the resonators in Nanoelectromechanical systems (NEMS). While nanoresonators' ability to attain high fundamental frequencies with excellent mechanical response makes them useful for high performance sensing, a critical performance measure is the quality factor of the resonator. While quality factors of single crystal materials have been extensively studied, few work has been done on the analysis of quality factors of nanocomposites. In this work, we investigate the characteristics of intrinsic energy dissipation in nanocomposite resonators using classical molecular dynamics. The quality factors, and thereby energy dissipation rate, of various silicon and germanium configurations are calculated. The relationship between the quality factor and the temperature, material configuration and interface area are investigated. Simulation results indicate that, due to the strong phonon scattering in the nanocomposite beams, the characteristics of the quality factor variation can not be described by the classical thermoelastic energy dissipation theory. The component material interface plays a major role in the quality factor of the beams. The disadvantageous effect of the interface area is significant, especially at lower temperatures. Advisors/Committee Members: Li, Gang, Thompson , Lonny L, Huang , Yong.

Subjects/Keywords: bond breaking; Carbon nanotubes; collision dynamics; molecular dynamics; nanocomposites; quality factors; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Annapaneni, P. (2011). MOLECULAR DYNAMICS STUDY OF PARTICLE IMPACT INDUCED BOND BREAKING OF SINGLE-WALLED CARBON NANOTUBES AND QUALITY FACTORS OF NANOCOMPOSITE STRUCTURES. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1163

Chicago Manual of Style (16^th Edition):

Annapaneni, Puroorava. “MOLECULAR DYNAMICS STUDY OF PARTICLE IMPACT INDUCED BOND BREAKING OF SINGLE-WALLED CARBON NANOTUBES AND QUALITY FACTORS OF NANOCOMPOSITE STRUCTURES.” 2011. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1163.

MLA Handbook (7^th Edition):

Annapaneni, Puroorava. “MOLECULAR DYNAMICS STUDY OF PARTICLE IMPACT INDUCED BOND BREAKING OF SINGLE-WALLED CARBON NANOTUBES AND QUALITY FACTORS OF NANOCOMPOSITE STRUCTURES.” 2011. Web. 20 Jan 2021.

Vancouver:

Annapaneni P. MOLECULAR DYNAMICS STUDY OF PARTICLE IMPACT INDUCED BOND BREAKING OF SINGLE-WALLED CARBON NANOTUBES AND QUALITY FACTORS OF NANOCOMPOSITE STRUCTURES. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1163.

Council of Science Editors:

Annapaneni P. MOLECULAR DYNAMICS STUDY OF PARTICLE IMPACT INDUCED BOND BREAKING OF SINGLE-WALLED CARBON NANOTUBES AND QUALITY FACTORS OF NANOCOMPOSITE STRUCTURES. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1163

Clemson University

16. Choragudi, Aditya sai nag. Finite Element Analysis Prediction of Stresses in H.L. Hunley Submarine by Global-to-Local Model Coordination.

Degree: MS, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1074

► H.L Hunley was a submarine of the Confederate States of America that participated in the American Civil War. On February 17, 1864, H.L.Hunley created history… (more)

Subjects/Keywords: Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Choragudi, A. s. n. (2011). Finite Element Analysis Prediction of Stresses in H.L. Hunley Submarine by Global-to-Local Model Coordination. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1074

Chicago Manual of Style (16^th Edition):

Choragudi, Aditya sai nag. “Finite Element Analysis Prediction of Stresses in H.L. Hunley Submarine by Global-to-Local Model Coordination.” 2011. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1074.

MLA Handbook (7^th Edition):

Choragudi, Aditya sai nag. “Finite Element Analysis Prediction of Stresses in H.L. Hunley Submarine by Global-to-Local Model Coordination.” 2011. Web. 20 Jan 2021.

Vancouver:

Choragudi Asn. Finite Element Analysis Prediction of Stresses in H.L. Hunley Submarine by Global-to-Local Model Coordination. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1074.

Council of Science Editors:

Choragudi Asn. Finite Element Analysis Prediction of Stresses in H.L. Hunley Submarine by Global-to-Local Model Coordination. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1074

Clemson University

17. Nainar, Naveen. ACOUSTIC PERFORMANCE OF REITERATED HIERARCHICAL HONEYCOMB STRUCTURES.

Degree: MS, Mechanical Engineering, 2015, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/2238

► Sandwich panels constructed from honeycomb structures have been found to reduce sound transmission and improve vibration isolation. In this work, reiterated hierarchical honeycomb structures have… (more)

▼ Sandwich panels constructed from honeycomb structures have been found to reduce sound transmission and improve vibration isolation. In this work, reiterated hierarchical honeycomb structures have been modeled for the core in sandwich panels and studied for sound transmission properties using finite element analysis. Several honeycomb unit cell geometries are considered, including, regular hexagonal, auxetic with properties of negative Poissonâ€™s ratio, and different reiterated hierarchical structures. Previous studies have shown that auxetic honeycomb structures exhibit improved sound transmission loss compared to regular honeycomb sandwich panels. Two different orientations of the honeycomb unit cell geometry have been studied, namely, the zigzag and armchair configurations, which are, rotated 90 degrees. Both regular and auxetic honeycombs have been used in both these configurations. The finite element model of the panels are used to extract natural frequencies and mode shapes and to perform steady state frequency response dynamic analysis up to 1000 Hz. The transmitted sound pressure levels on the surface of each structure is extracted and compared to study the influence of the reiterated hierarchy on sound transmission characteristics. The influence of corner reinforcement constructed by subtracting interior high-level hierarchical structure except at the vertices of the underlying lower-level honeycomb unit cell was also studied. Furthermore, a study was conducted to quantify the effect of changing the ratio of cell-wall thickness between various levels of hierarchy. Special focus on the limiting case of level-1 hierarchy with zero level-0 thickness is also studied. In all cases, the total mass was kept constant in order to isolate only stiffness and mass distribution effects. The results show that introduction of reiterated hierarchy in level-1 structures reduced the sound transmission of honeycomb sandwich panels compared to parent level-0 geometry. Results also showed that the corner reinforcement does not influence the sound transmission characteristics significantly, but does change the stiffness of the structure. For regular hexagonal honeycombs, changing the ratio of thickness between various levels of hierarchy did not affect the sound transmission significantly but made the structure stiffer when the ratio was increased, and reduced the stiffness when the ratio was decreased. For auxetic honeycomb structure, increasing the ratio made the structure less stiff, but reducing the ratio did not change the stiffness significantly. Advisors/Committee Members: Thompson, Lonny L, Li, Gang, Summers, Joshua D.

Subjects/Keywords: Hierarchical; Honeycomb; Reiterated; Sandwich panel; Sound pressure; Structural acoustics; Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Nainar, N. (2015). ACOUSTIC PERFORMANCE OF REITERATED HIERARCHICAL HONEYCOMB STRUCTURES. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/2238

Chicago Manual of Style (16^th Edition):

Nainar, Naveen. “ACOUSTIC PERFORMANCE OF REITERATED HIERARCHICAL HONEYCOMB STRUCTURES.” 2015. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/2238.

MLA Handbook (7^th Edition):

Nainar, Naveen. “ACOUSTIC PERFORMANCE OF REITERATED HIERARCHICAL HONEYCOMB STRUCTURES.” 2015. Web. 20 Jan 2021.

Vancouver:

Nainar N. ACOUSTIC PERFORMANCE OF REITERATED HIERARCHICAL HONEYCOMB STRUCTURES. [Internet] [Masters thesis]. Clemson University; 2015. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/2238.

Council of Science Editors:

Nainar N. ACOUSTIC PERFORMANCE OF REITERATED HIERARCHICAL HONEYCOMB STRUCTURES. [Masters Thesis]. Clemson University; 2015. Available from: https://tigerprints.clemson.edu/all_theses/2238

Clemson University

18. Cheruku, Bargav. MODELING AND FINITE ELEMENT ALAYSIS OF FLUID STRUCTURE INTERACTION IN A WIND ENERGY HARVESTER.

Degree: MS, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1161

► An energy harvesting system inspired by musicplaying harmonicas was developed for microwind power generation. The energy harvester uses flow-induced self-sustained oscillations of a piezoelectric beam… (more)

Subjects/Keywords: ANSYS CFX; ENERGY HARVESTING; FINITE ELEMENT ANALYSIS; FLUID STRUCTURE INTERACTION; REDUCED ORDER MODELING; SELF SUSTAINED OSCILLATIONS; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Cheruku, B. (2011). MODELING AND FINITE ELEMENT ALAYSIS OF FLUID STRUCTURE INTERACTION IN A WIND ENERGY HARVESTER. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1161

Chicago Manual of Style (16^th Edition):

Cheruku, Bargav. “MODELING AND FINITE ELEMENT ALAYSIS OF FLUID STRUCTURE INTERACTION IN A WIND ENERGY HARVESTER.” 2011. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1161.

MLA Handbook (7^th Edition):

Cheruku, Bargav. “MODELING AND FINITE ELEMENT ALAYSIS OF FLUID STRUCTURE INTERACTION IN A WIND ENERGY HARVESTER.” 2011. Web. 20 Jan 2021.

Vancouver:

Cheruku B. MODELING AND FINITE ELEMENT ALAYSIS OF FLUID STRUCTURE INTERACTION IN A WIND ENERGY HARVESTER. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1161.

Council of Science Editors:

Cheruku B. MODELING AND FINITE ELEMENT ALAYSIS OF FLUID STRUCTURE INTERACTION IN A WIND ENERGY HARVESTER. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1161

Clemson University

19. Mor, Arun. ACOUSTIC SCATTERING RESPONSE OF HIERARCHIC HONEYCOMB STRUCTURES FOR CYLINDRICAL AND SPHERICAL STRUCTURES.

Degree: MS, Mechanical Engineering, 2015, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/2187

► Sandwich panels with honeycomb core are often employed in structures for improved mechanical properties with lightweight. Honeycombs are defined by non-overlapping and periodic unit cells.… (more)

▼ Sandwich panels with honeycomb core are often employed in structures for improved mechanical properties with lightweight. Honeycombs are defined by non-overlapping and periodic unit cells. Most research conducted on these sandwich panels focuses on stiffness and strength properties. The acoustic aspect of these panels has been focused on sound transmission loss. For acoustics, previous studies used effective honeycomb orthotropic elastic moduli based on Cartesian unit cell geometry to model the core as a homogeneous structure. While efficient, this modeling approach loses accuracy at higher frequencies. Furthermore, when used for curved panels, the effective moduli are only approximate. In this work, mechanical and acoustic characteristics of cylindrical and spherical honeycomb panels are studied using finite element analysis. The unit cell geometry core is oriented both radially and in the transverse direction. The models are analyzed for sound scattering measured by target strength with interactions between structure and the acoustic medium through coupling between the domains. Both air and water are compared for the acoustic region. Different honeycomb core geometries varying in the hexagon arrangement, number of unit cells and level of hierarchy are studied. The structures developed are constrained to have the same total mass allowing for comparisons based on only changes in stiffness properties. The effect of face sheet thickness on the mechanical and acoustic properties of the curved sandwich structures is also studied. The vibration and acoustic scattering behavior of these structures have been investigated for natural frequencies between 1-1000 Hz to predict and understand the different responses near and at resonances. The target strength response of the structures has been studied in the near field at both front and back of the structures. The effect of acoustic coupling is observed clearly on varying the outer domains properties between air and water. It is noted that the acoustic scattering characteristics of the structures depend on the frequency of the incident wave and acoustic domain properties interacting with structures. When comparing honeycomb structures to a homogeneous structure with the same mass, for cylindrical structures the first few natural frequencies are lower compared to the reference homogeneous structure, and then increases for higher modes. In the case of the spherical structure, this behavior was reversed indicating the interaction between in-plane and out-of-plane stiffness of the 3-D sphere compared to the 2-D cylinder modes. Advisors/Committee Members: Thompson, Lonny L, Li, Gang, Summers, Joshua D.

Subjects/Keywords: Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Mor, A. (2015). ACOUSTIC SCATTERING RESPONSE OF HIERARCHIC HONEYCOMB STRUCTURES FOR CYLINDRICAL AND SPHERICAL STRUCTURES. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/2187

Chicago Manual of Style (16^th Edition):

Mor, Arun. “ACOUSTIC SCATTERING RESPONSE OF HIERARCHIC HONEYCOMB STRUCTURES FOR CYLINDRICAL AND SPHERICAL STRUCTURES.” 2015. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/2187.

MLA Handbook (7^th Edition):

Mor, Arun. “ACOUSTIC SCATTERING RESPONSE OF HIERARCHIC HONEYCOMB STRUCTURES FOR CYLINDRICAL AND SPHERICAL STRUCTURES.” 2015. Web. 20 Jan 2021.

Vancouver:

Mor A. ACOUSTIC SCATTERING RESPONSE OF HIERARCHIC HONEYCOMB STRUCTURES FOR CYLINDRICAL AND SPHERICAL STRUCTURES. [Internet] [Masters thesis]. Clemson University; 2015. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/2187.

Council of Science Editors:

Mor A. ACOUSTIC SCATTERING RESPONSE OF HIERARCHIC HONEYCOMB STRUCTURES FOR CYLINDRICAL AND SPHERICAL STRUCTURES. [Masters Thesis]. Clemson University; 2015. Available from: https://tigerprints.clemson.edu/all_theses/2187

Clemson University

20. Veeramurthy, Mallikarjun. Modeling, finite element analysis, and optimization of Non-Pneumatic Tire (NPT) for the minimization of rolling resistance.

Degree: MS, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1154

► Recently, the development of non-pneumatic tires (NPT) such as the Michelin Tweel is receiving increased attention due to potential advantages over pneumatic tires such as… (more)

Subjects/Keywords: Non-pneumatic tire; NPT; Optimization; Rolling resistance; Tire; Tweel; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Veeramurthy, M. (2011). Modeling, finite element analysis, and optimization of Non-Pneumatic Tire (NPT) for the minimization of rolling resistance. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1154

Chicago Manual of Style (16^th Edition):

Veeramurthy, Mallikarjun. “Modeling, finite element analysis, and optimization of Non-Pneumatic Tire (NPT) for the minimization of rolling resistance.” 2011. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1154.

MLA Handbook (7^th Edition):

Veeramurthy, Mallikarjun. “Modeling, finite element analysis, and optimization of Non-Pneumatic Tire (NPT) for the minimization of rolling resistance.” 2011. Web. 20 Jan 2021.

Vancouver:

Veeramurthy M. Modeling, finite element analysis, and optimization of Non-Pneumatic Tire (NPT) for the minimization of rolling resistance. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1154.

Council of Science Editors:

Veeramurthy M. Modeling, finite element analysis, and optimization of Non-Pneumatic Tire (NPT) for the minimization of rolling resistance. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1154

Clemson University

21. Ravichandraan, Krupakaran. STRUCTURAL OPTIMIZATION USING PARAMETRIC PROGRAMMING METHOD.

Degree: MS, Mechanical Engineering, 2015, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/2264

► The Parametric Programming method is investigated to consider its applicability to structural optimization problems. It is used to solve optimization problems that have design variables… (more)

▼ The Parametric Programming method is investigated to consider its applicability to structural optimization problems. It is used to solve optimization problems that have design variables as implicit functions of some independent input parameter(s). It provides optimal solutions as a parametric function of the input parameter(s) for the entire parameter space of interest. It does not require the detailed discrete optimizations needed at a large number of parameter values as in traditional non-parametric optimization. Parametric programming is widely used in optimal controls, model predictive control, scheduling, process synthesis and material design under uncertainty due to the above mentioned benefits. Its benefits are however, still unexplored in the field of structural optimization. Parametric programming could for instance, be used to aid designers in identifying and optimizing for uncertain loading conditions in complex systems. The first objective of this thesis is to identify a suitable multi-parametric programming algorithm among the many available ones in the literature to solve structural optimization problems. Once selected, the second goal is to implement the chosen algorithm and solve single parametric and multi-parametric sizing optimization problems, shape optimization problems, and use multi-parametric programming as a multi-objective optimization tool in structural optimization. In this regard, sizing optimization of truss structures and shape optimization of beams for load magnitude and load directions as varying parameters are solved for single and multi-parameter static and/or dynamic load cases. Parametric programming is also used to solve the multi-objective optimization of a honeycomb panel and the results are compared with those from non-parametric optimization conducted using commercial optimization software. Accuracy of results, and computational time are considered. From these studies, inferences are drawn about the issues and benefits of using parametric programming in structural optimization. Advisors/Committee Members: Fadel, Georges M, Wiecek, Margaret, Thompson, Lonny L.

Subjects/Keywords: Multiparametric Programming; Parametric Programming; Structural Optimization; Uncertain parameters; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ravichandraan, K. (2015). STRUCTURAL OPTIMIZATION USING PARAMETRIC PROGRAMMING METHOD. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/2264

Chicago Manual of Style (16^th Edition):

Ravichandraan, Krupakaran. “STRUCTURAL OPTIMIZATION USING PARAMETRIC PROGRAMMING METHOD.” 2015. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/2264.

MLA Handbook (7^th Edition):

Ravichandraan, Krupakaran. “STRUCTURAL OPTIMIZATION USING PARAMETRIC PROGRAMMING METHOD.” 2015. Web. 20 Jan 2021.

Vancouver:

Ravichandraan K. STRUCTURAL OPTIMIZATION USING PARAMETRIC PROGRAMMING METHOD. [Internet] [Masters thesis]. Clemson University; 2015. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/2264.

Council of Science Editors:

Ravichandraan K. STRUCTURAL OPTIMIZATION USING PARAMETRIC PROGRAMMING METHOD. [Masters Thesis]. Clemson University; 2015. Available from: https://tigerprints.clemson.edu/all_theses/2264

Clemson University

22. Trikuta Srinath, Ashwin. A novel approach to evaluating compact finite differences and similar tridiagonal schemes on GPU-accelerated clusters.

Degree: MS, Mechanical Engineering, 2015, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/2283

► Compact finite difference schemes are widely used in the direct numerical simulation of fluid flows for their ability to better resolve the small scales of… (more)

Subjects/Keywords: compact finite difference; computational fluid dynamics; direct numerical simulation; GPU; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Trikuta Srinath, A. (2015). A novel approach to evaluating compact finite differences and similar tridiagonal schemes on GPU-accelerated clusters. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/2283

Chicago Manual of Style (16^th Edition):

Trikuta Srinath, Ashwin. “A novel approach to evaluating compact finite differences and similar tridiagonal schemes on GPU-accelerated clusters.” 2015. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/2283.

MLA Handbook (7^th Edition):

Trikuta Srinath, Ashwin. “A novel approach to evaluating compact finite differences and similar tridiagonal schemes on GPU-accelerated clusters.” 2015. Web. 20 Jan 2021.

Vancouver:

Trikuta Srinath A. A novel approach to evaluating compact finite differences and similar tridiagonal schemes on GPU-accelerated clusters. [Internet] [Masters thesis]. Clemson University; 2015. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/2283.

Council of Science Editors:

Trikuta Srinath A. A novel approach to evaluating compact finite differences and similar tridiagonal schemes on GPU-accelerated clusters. [Masters Thesis]. Clemson University; 2015. Available from: https://tigerprints.clemson.edu/all_theses/2283

Clemson University

23. Chandrasekharan, Nataraj. ELECTROMECHANICAL MODELING OF A HONEYCOMB CORE INTEGRATED VIBRATION ENERGY CONVERTER WITH INCREASED SPECIFIC POWER FOR ENERGY HARVESTING APPLICATIONS.

Degree: PhD, Mechanical Engineering, 2015, Clemson University

URL: https://tigerprints.clemson.edu/all_dissertations/1558

► Innovation in integrated circuit technology along with improved manufacturing processes has resulted in considerable reduction in power consumption of electromechanical devices. Majority of these devices… (more)

▼ Innovation in integrated circuit technology along with improved manufacturing processes has resulted in considerable reduction in power consumption of electromechanical devices. Majority of these devices are currently powered by batteries. However, the issues posed by batteries, including the need for frequent battery recharge/replacement has resulted in a compelling need for alternate energy to achieve self-sufficient device operation or to supplement battery power. Vibration based energy harvesting methods through piezoelectric transduction provides with a promising potential towards replacing or supplementing battery power source. However, current piezoelectric energy harvesters generate low specific power (power-to-weight ratio) when compared to batteries that the harvesters seek to replace or supplement. In this study, the potential of integrating lightweight cellular honeycomb structures with existing piezoelectric device configurations (bimorph) to achieve higher specific power is investigated. It is shown in this study that at low excitation frequency ranges, replacing the solid continuous substrate of a conventional piezoelectric bimorph with honeycomb structures of the same material results in a significant increase in power-to-weight ratio of the piezoelectric harvester. In order to maximize the electrical response of vibration based power harvesters, the natural frequency of these harvesters is designed to match the input driving frequency. The commonly used technique of adding a tip mass is employed to lower the natural frequency (to match driving frequency) of both, solid and honeycomb substrate bimorphs. At higher excitation frequency, the natural frequency of the traditional solid substrate bimorph can only be altered (to match driving frequency) through a change in global geometric design parameters, typically achieved by increasing the thickness of the harvester. As a result, the size of the harvester is increased and can be disadvantageous especially if the application imposes a space/size constraint. Moreover, the bimorph with increased thickness will now require a larger mechanical force to deform the structure which can fall outside the input ambient excitation amplitude range. In contrast, the honeycomb core bimorph offers an advantage in terms of preserving the global geometric dimensions. The natural frequency of the honeycomb core bimorph can be altered by manipulating honeycomb cell design parameters, such as cell angle, cell wall thickness, vertical cell height and inclined cell length. This results in a change in the mass and stiffness properties of the substrate and hence the bimorph, thereby altering the natural frequency of the harvester. Design flexibility of honeycomb core bimorphs is demonstrated by varying honeycomb cell parameters to alter mass and stiffness properties for power harvesting. The influence of honeycomb cell parameters on power generation is examined to evaluate optimum design to attain highest specific power. In addition, the more compliant nature of… Advisors/Committee Members: Thompson, Lonny, Li, Gang, Daqaq, Mohammed, Zhao, Huijuan.

Subjects/Keywords: Energy harvesting; Honeycomb; Piezoelectric; Specific power; Vibration; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Chandrasekharan, N. (2015). ELECTROMECHANICAL MODELING OF A HONEYCOMB CORE INTEGRATED VIBRATION ENERGY CONVERTER WITH INCREASED SPECIFIC POWER FOR ENERGY HARVESTING APPLICATIONS. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/1558

Chicago Manual of Style (16^th Edition):

Chandrasekharan, Nataraj. “ELECTROMECHANICAL MODELING OF A HONEYCOMB CORE INTEGRATED VIBRATION ENERGY CONVERTER WITH INCREASED SPECIFIC POWER FOR ENERGY HARVESTING APPLICATIONS.” 2015. Doctoral Dissertation, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_dissertations/1558.

MLA Handbook (7^th Edition):

Chandrasekharan, Nataraj. “ELECTROMECHANICAL MODELING OF A HONEYCOMB CORE INTEGRATED VIBRATION ENERGY CONVERTER WITH INCREASED SPECIFIC POWER FOR ENERGY HARVESTING APPLICATIONS.” 2015. Web. 20 Jan 2021.

Vancouver:

Chandrasekharan N. ELECTROMECHANICAL MODELING OF A HONEYCOMB CORE INTEGRATED VIBRATION ENERGY CONVERTER WITH INCREASED SPECIFIC POWER FOR ENERGY HARVESTING APPLICATIONS. [Internet] [Doctoral dissertation]. Clemson University; 2015. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/1558.

Council of Science Editors:

Chandrasekharan N. ELECTROMECHANICAL MODELING OF A HONEYCOMB CORE INTEGRATED VIBRATION ENERGY CONVERTER WITH INCREASED SPECIFIC POWER FOR ENERGY HARVESTING APPLICATIONS. [Doctoral Dissertation]. Clemson University; 2015. Available from: https://tigerprints.clemson.edu/all_dissertations/1558

Clemson University

24. Xu, Yaoyao. MODELING OF STRAIN EFFECT ON THERMAL AND ELECTRICAL TRANSPORT PROPERTIES OF SI/GE NANOCOMPOSITES AND ITS APPLICATIONS.

Degree: PhD, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_dissertations/778

► Nanocomposites are composite materials which incorporate nanosized particles, platelets or fibers. The addition of nanosized phases into the bulk matrix can lead to significantly different… (more)

▼ Nanocomposites are composite materials which incorporate nanosized particles, platelets or fibers. The addition of nanosized phases into the bulk matrix can lead to significantly different material properties compared to their macrocomposite counterparts. Due to their extraordinary properties, nanocomposites promise new applications in many fields such as ultra-high strength and ultra-light automotive parts, non-linear optics, biomedical applications, sensors and actuators, and thermoelectric devices. The design and fabrication of nanocomposite structures, devices and systems can be accelerated by developing accurate and efficient computational tools that can describe the properties and behavior of the nanocomposites. However, the development of such tools is challenging due to the multiscale nature of the materials. In addition, many devices where nanocomposites are employed are multiphysics systems with interactions of the mechanical, thermal and electrical energy domains. In such systems, while mechanical deformation is dependent on the temperature change, the thermal and electrical transport properties are functions of mechanical strain. In this work, we develop theoretical and computational models to address these issues and investigate the strain effect on the thermal and electrical transport properties in Si/Ge nanocomposites. We model strain effect on the phonon thermal conductivities in the Si/Ge nanocomposite materials by combining the strain dependent lattice dynamics and the ballistic phonon Boltzmann transport equation (BTE). The Seebeck coefficient and electrical conductivity of the Si/Ge nanocomposites are calculated by using an analytical model derived from the BTE under the relaxation-time approximation. The effect of strain is incorporated into the analytical model through strain induced energy shift and effective mass variation calculated from the deformation potential theory and a degenerate kp method at the zone-boundary X point. By using the models, strain effect on the thermoelectric figure of merit is investigated for n-type Si/Ge nanocomposite materials. Our calculations reveal that in the 300 − 800 K temperature range, uniaxial tensile strain along < 100 > direction increases dimensionless figure of merit parallel to the tension, and biaxial tensile strain along [100] and [010] directions decreases it at low temperatures and increases it at high temperatures in the tension directions. Shear strain and compressive uniaxial and biaxial strains decrease the figure of merit. At 800K with an electron concentration of 10¹⁹/cm³, 1% uniaxial tensile strain can increase the figure of merit of Si(0.8)Ge(0.2) nanocomposites by as much as 14%. In light of nanocomposites' high electrical to thermal conductivity ratio, we propose to use Si/Ge nanocomposite materials to improve the performance of micro thermal actuators. The high electrical to thermal conductivity ratio of Si/Ge nanocomposites is utilized to facilitate a rapid temperature change within a short distance,… Advisors/Committee Members: Li, Gang, Biggers , Sherrill B., Joseph , Paul F., Thompson , Lonny L..

Subjects/Keywords: Nanoscience and Nanotechnology

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Xu, Y. (2011). MODELING OF STRAIN EFFECT ON THERMAL AND ELECTRICAL TRANSPORT PROPERTIES OF SI/GE NANOCOMPOSITES AND ITS APPLICATIONS. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/778

Chicago Manual of Style (16^th Edition):

Xu, Yaoyao. “MODELING OF STRAIN EFFECT ON THERMAL AND ELECTRICAL TRANSPORT PROPERTIES OF SI/GE NANOCOMPOSITES AND ITS APPLICATIONS.” 2011. Doctoral Dissertation, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_dissertations/778.

MLA Handbook (7^th Edition):

Xu, Yaoyao. “MODELING OF STRAIN EFFECT ON THERMAL AND ELECTRICAL TRANSPORT PROPERTIES OF SI/GE NANOCOMPOSITES AND ITS APPLICATIONS.” 2011. Web. 20 Jan 2021.

Vancouver:

Xu Y. MODELING OF STRAIN EFFECT ON THERMAL AND ELECTRICAL TRANSPORT PROPERTIES OF SI/GE NANOCOMPOSITES AND ITS APPLICATIONS. [Internet] [Doctoral dissertation]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/778.

Council of Science Editors:

Xu Y. MODELING OF STRAIN EFFECT ON THERMAL AND ELECTRICAL TRANSPORT PROPERTIES OF SI/GE NANOCOMPOSITES AND ITS APPLICATIONS. [Doctoral Dissertation]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_dissertations/778

Clemson University

25. Wang, Wenshan. Network Target Coordination for Design Optimization of Decomposed Systems.

Degree: PhD, Mechanical Engineering, 2012, Clemson University

URL: https://tigerprints.clemson.edu/all_dissertations/1071

► A complex engineered system is often decomposed into a number of different subsystems that interact on one another and together produce results not obtainable by… (more)

▼ A complex engineered system is often decomposed into a number of different subsystems that interact on one another and together produce results not obtainable by the subsystems alone. Effective coordination of the interdependencies shared among these subsystems is critical to fulfill the stakeholder expectations and technical requirements of the original system. The past research has shown that various coordination methods obtain different solution accuracies and exhibit different computational efficiencies when solving a decomposed system. Addressing these coordination decisions may lead to improved complex system design. This dissertation studies coordination methods through two types of decomposition structures, hierarchical, and nonhierarchical. For coordinating hierarchically decomposed systems, linear and proximal cutting plane methods are applied based on augmented Lagrangian relaxation and analytical target cascading (ATC). Three nonconvex, nonlinear design problems are used to verify the numerical performance of the proposed coordination method and the obtained results are compared to traditional update schemes of subgradient-based algorithm. The results suggest that the cutting plane methods can significantly improve the solution accuracy and computational efficiency of the hierarchically decomposed systems. In addition, a biobjective optimization method is also used to capture optimality and feasibility. The numerical performance of the biobjective algorithm is verified by solving an analytical mass allocation problem. For coordinating nonhierarchically decomposed complex systems, network target coordination (NTC) is developed by modeling the distributed subsystems as different agents in a network. To realize parallel computing of the subsystems, NTC via a consensus alternating direction method of multipliers is applied to eliminate the use of the master problem, which is required by most distributed coordination methods. In NTC, the consensus is computed using a locally update scheme, providing the potential to realize an asynchronous solution process. The numerical performance of NTC is verified using a geometrical programming problem and two engineering problems. Advisors/Committee Members: Fadel, Georges M, Li , Gang, Thompson , Lonny L, Wiecek , Margaret M.

Subjects/Keywords: Alternating Direction Method of Multipliers; Analytical Target Cascading; Consensus Optimization; Cutting Plane Methods; Multidisciplinary Design Optimization; Network Target Cascading; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, W. (2012). Network Target Coordination for Design Optimization of Decomposed Systems. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/1071

Chicago Manual of Style (16^th Edition):

Wang, Wenshan. “Network Target Coordination for Design Optimization of Decomposed Systems.” 2012. Doctoral Dissertation, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_dissertations/1071.

MLA Handbook (7^th Edition):

Wang, Wenshan. “Network Target Coordination for Design Optimization of Decomposed Systems.” 2012. Web. 20 Jan 2021.

Vancouver:

Wang W. Network Target Coordination for Design Optimization of Decomposed Systems. [Internet] [Doctoral dissertation]. Clemson University; 2012. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/1071.

Council of Science Editors:

Wang W. Network Target Coordination for Design Optimization of Decomposed Systems. [Doctoral Dissertation]. Clemson University; 2012. Available from: https://tigerprints.clemson.edu/all_dissertations/1071

Clemson University

26. Schultz, Jesse. Modeling and Finite Element Analysis Methods for the Dynamic Crushing of Honeycomb Cellular Meso-Structures.

Degree: MS, Mechanical Engineering, 2011, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1106

► The effective static mechanical properties, such as the moduli of elasticity and rigidity and Poisson's ratio, of honeycomb cellular meso-structures are capable of control due… (more)

Subjects/Keywords: Cellular Materials; FEA; Honeycomb; Impact; Meso-structures; Meta-Materials; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Schultz, J. (2011). Modeling and Finite Element Analysis Methods for the Dynamic Crushing of Honeycomb Cellular Meso-Structures. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1106

Chicago Manual of Style (16^th Edition):

Schultz, Jesse. “Modeling and Finite Element Analysis Methods for the Dynamic Crushing of Honeycomb Cellular Meso-Structures.” 2011. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1106.

MLA Handbook (7^th Edition):

Schultz, Jesse. “Modeling and Finite Element Analysis Methods for the Dynamic Crushing of Honeycomb Cellular Meso-Structures.” 2011. Web. 20 Jan 2021.

Vancouver:

Schultz J. Modeling and Finite Element Analysis Methods for the Dynamic Crushing of Honeycomb Cellular Meso-Structures. [Internet] [Masters thesis]. Clemson University; 2011. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1106.

Council of Science Editors:

Schultz J. Modeling and Finite Element Analysis Methods for the Dynamic Crushing of Honeycomb Cellular Meso-Structures. [Masters Thesis]. Clemson University; 2011. Available from: https://tigerprints.clemson.edu/all_theses/1106

Clemson University

27. Czech, Christopher. Design of Meta-Materials Outside the Homogenization Limit Using Multiscale Analysis and Topology Optimization.

Degree: PhD, Mechanical Engineering, 2012, Clemson University

URL: https://tigerprints.clemson.edu/all_dissertations/900

► The field of meta-materials engineering has largely expanded mechanical design possibilities over the last two decades; some notable design advances include the systematic engineering of… (more)

▼ The field of meta-materials engineering has largely expanded mechanical design possibilities over the last two decades; some notable design advances include the systematic engineering of negative Poisson's ratio materials and functionally graded materials, materials designed for optimal electronic and thermo-mechanical performances, and the design of materials under uncertainty. With these innovations, the systematic engineering of materials for design-specific uses is becoming more common in industrial and military uses. The motivation for this body of research is the design of the shear beam for a non-pneumatic wheel. Previously, a design optimization of a finite element model of the non-pneumatic wheel was completed, where a linear elastic material was simulated in the shear beam to reduce hysteretic energy losses. As part of the optimization, a set of optimal orthotropic material properties and other geometric properties were identified for the shear beam. Given that no such natural linear elastic material exists, a meta-material can be engineered that meets these properties using the aforementioned tools. However, manufacturing constraints prevent the use of standard homogenization analysis and optimization tools in the engineering of the shear beam due to limitations in the accuracy of the homogenization process for thin materials. In this research, the more general volume averaging analysis is shown to be an accurate tool for meta-material analysis for engineering thin-layered materials. Given an accurate analysis method, several optimization formulations are proposed, and optimality conditions are derived to determine the most mathematically feasible and numerically reliable formulation for topology optimization of a material design problem using a continuous material interpolation over the design domain. This formulation is implemented to engineer meta-materials for problems using the volume averaging analysis, which includes the use of variable linking and the derivation of first-order design sensitivities to increase computational efficiency. Inspired by honeycomb materials, a new method of discretizing the material design domain into unit cells with non-simple connectivity is proposed as a way of increasing the solution space of the topology optimization problem. Finally, these methods are used in the meta-material design process to identify several candidate meta-material geometries from a polycarbonate base material for the shear layer of the non-pneumatic wheel; notable geometries include an `x'-like geometry, a bent column-like geometry identified previously as a bristle, and, remarkably, an auxetic honeycomb geometry. This is the first reported result demonstrating the auxetic honeycomb geometry to be a minimum weight structure in shear loading where a general topology optimization method was used. Advisors/Committee Members: Fadel, Georges, Guarneri , Paolo, Thompson , Lonny, Li , Gang, Wiecek , Margaret, Gibert , James.

Subjects/Keywords: Homogenization; Metamaterials; Multiscale Analysis; Optimization; Topology Optimization; Mechanical Engineering

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Czech, C. (2012). Design of Meta-Materials Outside the Homogenization Limit Using Multiscale Analysis and Topology Optimization. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/900

Chicago Manual of Style (16^th Edition):

Czech, Christopher. “Design of Meta-Materials Outside the Homogenization Limit Using Multiscale Analysis and Topology Optimization.” 2012. Doctoral Dissertation, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_dissertations/900.

MLA Handbook (7^th Edition):

Czech, Christopher. “Design of Meta-Materials Outside the Homogenization Limit Using Multiscale Analysis and Topology Optimization.” 2012. Web. 20 Jan 2021.

Vancouver:

Czech C. Design of Meta-Materials Outside the Homogenization Limit Using Multiscale Analysis and Topology Optimization. [Internet] [Doctoral dissertation]. Clemson University; 2012. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_dissertations/900.

Council of Science Editors:

Czech C. Design of Meta-Materials Outside the Homogenization Limit Using Multiscale Analysis and Topology Optimization. [Doctoral Dissertation]. Clemson University; 2012. Available from: https://tigerprints.clemson.edu/all_dissertations/900

28. Wang, Xin. THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF SOUND TRANSMISSION PERFORMANCE OF HONEYCOMB SANDWICH STRUCTURES.

Degree: MS, Mechanical Engineering, 2013, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1672

► Due to the lighter weight of honeycomb structures compared with a cuboid of similar material, honeycomb is widely used in applications requiring a high… (more)

▼ Due to the lighter weight of honeycomb structures compared with a cuboid of similar material, honeycomb is widely used in applications requiring a high stiffness to weight ratio. One important honeycomb meta-structure is sandwich composites designed with a honeycomb core between two thin panel layers. The geometry of the honeycomb is formed from periodically spaced, non-overlapping unit cells. An important advantage of cellular materials such as honeycomb is that vibration and acoustic properties can be changed simply by changing the unit cell geometry variables such as included angle, cell wall thickness and length, while keeping the overall dimensions of the structure unchanged. Previous investigators have studied the vibration and sound transmission loss (STL) properties of honeycomb sandwich structures subjected to in-plane loading. In these studies, two-dimensional (2D) finite element models were sufficient to obtain solutions. In the present work, the sound transmission performance of honeycomb for out-of-plane loading is investigated, requiring a complete three-dimensional (3D) structural-acoustics model. In order to obtain efficient finite element solutions for a 3D model, a prolate spheroidal impedance boundary is used to truncate the unbounded acoustic region. The impedance boundary is designed to approximate the far-field acoustic radiation condition and absorb outgoing waves without reflection. The accuracy of this impedance boundary depends on the distance from the sound source, in this case the vibrating honeycomb structure, and frequency. In the present work, a 2D structural-acoustic finite element model with an elliptical non-reflecting impedance boundary is used to provide guidelines for generalization to the 3D model with a prolate spheroidal boundary. The 2D model provides fast STL solutions, for multiple model design evaluations, for selection of the smallest dimension which provides a reduced computational domain, while still maintaining similar accuracy to a circular (spherical) boundary with a much larger distance. Using the 3D finite element modeling procedure developed, natural frequencies and mode shapes are calculated to determine frequency ranges of interest for a steady-state analysis of a honeycomb sandwich panel coupled with the acoustic region subject to a time-harmonic pressure load. The effects of honeycomb unit cell geometry; both positive cell wall (regular) and negative angles (auxetic), on the sound transmission performance are compared. Relationships are observed between the number and frequency locations of peak amplitudes in STL response to the number of positive and negative normal amplitude regions in the mode shapes of the honeycomb structure. It is found that peaks in STL occur only when the number of positive amplitude mode shape regions is different from the number of negative regions. When the numbers of positive and negative amplitude regions are different, the amount of sound transmitted through the honeycomb structure is large. In contrast, when the… Advisors/Committee Members: Thompson, Lonny, Daqaq , Mohammed, Zhao , Huijuan.

Subjects/Keywords: Mechanical Engineering

10 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Wang, X. (2013). THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF SOUND TRANSMISSION PERFORMANCE OF HONEYCOMB SANDWICH STRUCTURES. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1672

Chicago Manual of Style (16^th Edition):

Wang, Xin. “THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF SOUND TRANSMISSION PERFORMANCE OF HONEYCOMB SANDWICH STRUCTURES.” 2013. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1672.

MLA Handbook (7^th Edition):

Wang, Xin. “THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF SOUND TRANSMISSION PERFORMANCE OF HONEYCOMB SANDWICH STRUCTURES.” 2013. Web. 20 Jan 2021.

Vancouver:

Wang X. THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF SOUND TRANSMISSION PERFORMANCE OF HONEYCOMB SANDWICH STRUCTURES. [Internet] [Masters thesis]. Clemson University; 2013. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1672.

Council of Science Editors:

Wang X. THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF SOUND TRANSMISSION PERFORMANCE OF HONEYCOMB SANDWICH STRUCTURES. [Masters Thesis]. Clemson University; 2013. Available from: https://tigerprints.clemson.edu/all_theses/1672

29. Surabhi, Akhilesh. Finite element beam model for piezoelectric energy harvesting using higher order shear deformation theory.

Degree: MS, Mechanical Engineering, 2014, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1906

► Piezoelectric energy harvesting devices convert mechanical energy to usable electrical energy, which can be used to power other electronic devices and sensors. Typical piezoelectric… (more)

▼ Piezoelectric energy harvesting devices convert mechanical energy to usable electrical energy, which can be used to power other electronic devices and sensors. Typical piezoelectric harvesters are unimorph cantilever composite beams, which have a single active piezoceramic layer and a passive substrate or a bimorph that has a passive substrate sandwiched between two piezoceramic layers. Power is captured across a coupled load resistor circuit in either a series or parallel connection. The mathematical modeling approaches for piezoelectric beam harvesters present in literature range from analytical distributed parameter modeling, to approximate distributed parameter, Rayleigh- Ritz global discretization or finite element local discretization. For slender electromechanical beam devices, the Classical Beam Theory, which assumes that transverse shear strain is zero, predicts natural frequencies accurately for lower frequencies. First Order Beam Theory accounts for transverse shear deformation in beam bending, but assumes that the shear strain and stress is constant through the thickness and the shear stiffness must be adjusted with a shear correction factor as an approximation. The shear correction factor depends on the lamina material properties and so for composite beams, a model, which does not require the use of shear correction factor, is desirable. In the present work, a beam finite element model based on a high-order parabolic shear deformation theory for multi-layered composite piezoelectric beam energy harvesting device is developed. The proposed mathematical model based on the Higher Order Shear Deformation Theory accounts not only for transverse shear strains, but also for a parabolic variation of the transverse shear strains through thickness. This satisfies the zero transverse shear stresses condition on the boundary planes and consequently, there is no need for a shear correction factor. A layerwise theory is used to model the electric potential in the thickness direction, with a fully coupled load resistor circuit in both series and parallel configurations. The beam element uses four mechanical degrees-of-freedom per node, axial displacement, transverse displacement, slope, and independent section rotation angle. Comparisons of the natural frequencies, steady-state power and voltage values from time-harmonic base excitation obtained from piezoelectric bimorph cantilever beams using the Euler-Bernoulli, Timoshenko and the higher order shear deformation theory are presented. Comparisons for the different shear deformation theories are presented for different length-to-depth aspect ratios. The results show increased accuracy for steady-state power solutions using the higher-order beam elements for moderately thick beams at higher frequencies. Advisors/Committee Members: Thompson, Lonny, Daqaq , Mohammed, Li , Gang.

Subjects/Keywords: Classical Beam Theory; Electromechanical coupling; Finite element analysis; First order shear deformation theory; Higher order shear deformation theory; Piezoelectric energy harvesting; Mechanical Engineering

4 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Surabhi, A. (2014). Finite element beam model for piezoelectric energy harvesting using higher order shear deformation theory. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1906

Chicago Manual of Style (16^th Edition):

Surabhi, Akhilesh. “Finite element beam model for piezoelectric energy harvesting using higher order shear deformation theory.” 2014. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1906.

MLA Handbook (7^th Edition):

Surabhi, Akhilesh. “Finite element beam model for piezoelectric energy harvesting using higher order shear deformation theory.” 2014. Web. 20 Jan 2021.

Vancouver:

Surabhi A. Finite element beam model for piezoelectric energy harvesting using higher order shear deformation theory. [Internet] [Masters thesis]. Clemson University; 2014. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1906.

Council of Science Editors:

Surabhi A. Finite element beam model for piezoelectric energy harvesting using higher order shear deformation theory. [Masters Thesis]. Clemson University; 2014. Available from: https://tigerprints.clemson.edu/all_theses/1906

30. Evans, Matthew. Modal Analysis to Minimize Gearbox Induced Noise of General Electric Wind Turbines.

Degree: MS, Mechanical Engineering, 2013, Clemson University

URL: https://tigerprints.clemson.edu/all_theses/1622

► With the current global emphasis on alternative green energy sources, wind turbine technologies have seen significant growth in recent years. Today, wind turbines are… (more)

▼ With the current global emphasis on alternative green energy sources, wind turbine technologies have seen significant growth in recent years. Today, wind turbines are being produced and constructed at unprecedented levels with their sites inching closer and closer to residential communities. With that, wind turbine companies have been receiving growing complains about the noise emitted from these turbines during operation. To resolve this issue, many of these companies are spending more resources to design and manufacture quieter wind turbines. In particular, General Electric (GE) intends to reduce the noise created by their 2.5 MW CGDT wind turbines. Previous studies showed that noise starts in the gearbox due to the transmission error between the meshing gears which creates extensive vibrations. These vibrations resonate with the gearbox housing causing energy to propagate from the housing to the bedplate and then to the nacelle. Vibrations are then transmitted from the nacelle to the rotating blades which produce a humming sound (noise) in the surroundings. GE researchers have theorized that noise can be eliminated if the gearbox housing is designed such that its modal frequencies are far from the excitation frequencies resulting from the transmission error. In order to achieve this goal, this thesis aims to develop a computational model which captures the modal response of the gearbox housing. Once this model is developed and validated against experimental data, alterations to the design can be implemented to shift the trouble frequencies. Two computational models are developed using the commercial softwares ANSYS and MASTA. The ANSYS model, which imposes several simplifying assumptions on the dynamics, is shown to lack the accuracy necessary to capture the modal response of the gearbox housing. The MASTA model, on the other hand, includes the interactions between the gearbox dynamics and the housing and is shown to produce modal responses that match the experimental data. The model and techniques provided in this thesis will provide the springboard upon which future design improvements and noise reduction techniques of GE wind turbines are launched. Advisors/Committee Members: Daqaq, Mohammed F, Thompson , Lonny, Li , Gang.

Subjects/Keywords: Gearbox noise; modal analysis; wind turbines; Mechanical Engineering

14 more images…

Record Details Similar Records Cite « Share

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Evans, M. (2013). Modal Analysis to Minimize Gearbox Induced Noise of General Electric Wind Turbines. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/1622

Chicago Manual of Style (16^th Edition):

Evans, Matthew. “Modal Analysis to Minimize Gearbox Induced Noise of General Electric Wind Turbines.” 2013. Masters Thesis, Clemson University. Accessed January 20, 2021. https://tigerprints.clemson.edu/all_theses/1622.

MLA Handbook (7^th Edition):

Evans, Matthew. “Modal Analysis to Minimize Gearbox Induced Noise of General Electric Wind Turbines.” 2013. Web. 20 Jan 2021.

Vancouver:

Evans M. Modal Analysis to Minimize Gearbox Induced Noise of General Electric Wind Turbines. [Internet] [Masters thesis]. Clemson University; 2013. [cited 2021 Jan 20]. Available from: https://tigerprints.clemson.edu/all_theses/1622.

Council of Science Editors:

Evans M. Modal Analysis to Minimize Gearbox Induced Noise of General Electric Wind Turbines. [Masters Thesis]. Clemson University; 2013. Available from: https://tigerprints.clemson.edu/all_theses/1622

		in
And / Or
		in
And / Or
		in
And / Or
		in

Open Access Theses and Dissertations