subject:(Poisson s ratio)

RMIT University

1. Du, X. Topology optimisation of composites with base materials of distinct Poisson’s ratios.

Degree: 2017, RMIT University

URL: http://researchbank.rmit.edu.au/view/rmit:162166

► Structural topology optimization approaches help engineers to find the best layout or configuration of members in structural systems. However, these approaches differ in terms of… (more)

▼ Structural topology optimization approaches help engineers to find the best layout or configuration of members in structural systems. However, these approaches differ in terms of computational costs and efficiency, quality of generated topologies, robustness, and the level of effort for implantation as a computational post-processing procedure. On the other hand, one common approach for saving resources is the application of porous or composite materials that have extreme or tailored properties. It is known that composite materials with improved properties can be designed by modifications into the topology of their microstructures. A systematic way for improving the properties of these types of materials consists of application of a structural topology optimization approach to find the best spatial distribution of materials within the microstructures of composites. This study presents new approaches for design of microstructures for materials based on the bidirectional evolutionary structural optimization (BESO) methodology. It is assumed that the materials are composed of repeating microstructures known as periodic base cells (PBC). The goal is to apply the BESO topology optimization to find the best spatial distribution of constituent phases within the PBC in such a way that materials with desired or improved functional properties are achieved. To this end, the homogenization theory is applied to establish a relationship between material properties in microstructural and macrostructural length scales. In the first stage of this study, the optimization problem is formulated to find microstructures for composites of prescribed volume constrains with maximum effective Young's moduli. It is assumed that the base materials are composed of two materials with different Poisson’s ratios. By performing finite element analysis on the PBC and applying the homogenization theory, an elemental sensitivity analysis is conducted. Following by removing and adding elements gradually in an iterative process according to their sensitivity ranking, the optimal topology for the PBC can be generated. The effectiveness and computational efficiency of the proposed approach is numerically exemplified through a range of 3D topology optimization problems. In the next stage of this study, the optimization problem is formulated to find microstructures for composites of prescribed volume constrains with maximum stiffness in the form of bulk or shear modulus. Here the composites possess two constituent phases. Compared with cellular materials whose microstructures are made of a solid phase and a void phase, composites of two different material phases are more advantageous since they can provide a wider range of performance characteristics. Maximization of bulk or shear modulus subject to a volumetric constraint is selected as the objective of the material design. Adding and removing of elements is performed based on the ranking of sensitivity numbers and imposed volumetric constraint between different base materials. The…

Subjects/Keywords: Fields of Research; Topology optimization; Composite material; Poisson'; s ratio; BESO; Homogenization

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APA (6^th Edition):

Du, X. (2017). Topology optimisation of composites with base materials of distinct Poisson’s ratios. (Thesis). RMIT University. Retrieved from http://researchbank.rmit.edu.au/view/rmit:162166

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Du, X. “Topology optimisation of composites with base materials of distinct Poisson’s ratios.” 2017. Thesis, RMIT University. Accessed March 08, 2021. http://researchbank.rmit.edu.au/view/rmit:162166.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Du, X. “Topology optimisation of composites with base materials of distinct Poisson’s ratios.” 2017. Web. 08 Mar 2021.

Vancouver:

Du X. Topology optimisation of composites with base materials of distinct Poisson’s ratios. [Internet] [Thesis]. RMIT University; 2017. [cited 2021 Mar 08]. Available from: http://researchbank.rmit.edu.au/view/rmit:162166.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Du X. Topology optimisation of composites with base materials of distinct Poisson’s ratios. [Thesis]. RMIT University; 2017. Available from: http://researchbank.rmit.edu.au/view/rmit:162166

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

RMIT University

2. Ren, X. Studies on three-dimensional metamaterials and tubular structures with negative Poisson’s ratio.

Degree: 2017, RMIT University

URL: http://researchbank.rmit.edu.au/view/rmit:162197

► Materials and structures with negative Poisson’s ratio exhibit counter-intuitive behaviour, i.e., under uniaxial compression (tension), these materials and structures contract (expand) transversely. The materials and… (more)

▼ Materials and structures with negative Poisson’s ratio exhibit counter-intuitive behaviour, i.e., under uniaxial compression (tension), these materials and structures contract (expand) transversely. The materials and structures that possess this feature are also called ‘auxetics’ by Evans. The terminology of ‘auxetic’ becomes a common adjective to describe materials and structures with negative Poisson’s ratio. Many desirable properties resulting from this unusual behaviour have been reported, e.g., higher shear resistance, indentation resistance, fracture resistance, improved acoustic and higher energy absorption, synclastic behaviour and variable permeability. These superior properties offer auxetics broad potential applications, e.g., smart filters, sensors, medical devices and protective equipment. However, there are still many challenging problems which impede wider applications of auxetics. First of all, most of the studied auxetic materials are two-dimensional (2D) and very few three-dimensional (3D) auxetic materials have been designed and investigated. Secondly, the base materials of the most existing auxetic metamaterials are rubber-like materials, hence these auxetic metamaterials are limited to the elastic deformation. In contrast to elastic auxetic metamaterials, metallic auxetic metamaterials exhibit some new features in mechanical properties, e.g., localisation of plastic strain, strain hardening and irreversible deformation. Furthermore, metallic metamaterials are usually stronger than those made of elastomers, which leads to superior loading resistance and energy absorption. Last but not the least, although most of the publications mention that auxetic materials possess many desirable properties, very few auxetic materials have been designed and fabricated to the practical stage. Therefore, it is worthy of carrying out more original research to explore new applications for auxetic materials. In order to fill the research gap mentioned above and create better auxetic materials for applications, in this study, extensive numerical and experimental investigations have been conducted. Firstly, a novel methodology was proposed to generate a 3D metallic cubic auxetic material based on a cubic buckling-induced auxetic material. It was found that the base material affected the auxetic behaviour of the buckling-induced cubic auxetic materials. When the elastomer base material was replaced with a ductile metallic material, the previously observed auxetic behaviour of the buckling-induced auxetic material would disappear. Inspired by this unexpected behaviour, a new methodology of generating 3D metallic auxetic materials was developed. The effectiveness of the methodology was then proved experimentally and numerically. The mechanical properties of the designed 3D metallic auxetic materials could be easily tuned by one single parameter of pattern scale factor (PSF). In the second part of this study, a simple auxetic tubular structure which exhibited…

Subjects/Keywords: Fields of Research; Auxetic; negative Poisson'; s ratio; metamaterials; structures; Auxetics

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

APA (6^th Edition):

Ren, X. (2017). Studies on three-dimensional metamaterials and tubular structures with negative Poisson’s ratio. (Thesis). RMIT University. Retrieved from http://researchbank.rmit.edu.au/view/rmit:162197

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Ren, X. “Studies on three-dimensional metamaterials and tubular structures with negative Poisson’s ratio.” 2017. Thesis, RMIT University. Accessed March 08, 2021. http://researchbank.rmit.edu.au/view/rmit:162197.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Ren, X. “Studies on three-dimensional metamaterials and tubular structures with negative Poisson’s ratio.” 2017. Web. 08 Mar 2021.

Vancouver:

Ren X. Studies on three-dimensional metamaterials and tubular structures with negative Poisson’s ratio. [Internet] [Thesis]. RMIT University; 2017. [cited 2021 Mar 08]. Available from: http://researchbank.rmit.edu.au/view/rmit:162197.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Ren X. Studies on three-dimensional metamaterials and tubular structures with negative Poisson’s ratio. [Thesis]. RMIT University; 2017. Available from: http://researchbank.rmit.edu.au/view/rmit:162197

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Penn State University

3. Kosarian, Minoo. Lithospheric Structure of North Africa and Western Eurasia .

Degree: 2008, Penn State University

URL: https://submit-etda.libraries.psu.edu/catalog/7387

► Although much progress has been made over the last few decades towards understanding the structure of the Earth, many questions regarding the details of Earth's… (more)

▼ Although much progress has been made over the last few decades towards understanding the structure of the Earth, many questions regarding the details of Earth's lithospheric structure remain unanswered. The primary goal of this study is to gain a better understanding of upper and lower continental crustal composition and structure to improve our knowledge of the tectonic evolution of the Earth. To contribute this goal, the present study focuses on the estimation of first order seismic structure using receiver functions, and the construction of a library of shear-velocity structures in the vicinity of seismic stations across western Eurasia and north Africa using receiver functions and tomography based surface wave dispersion estimates. One hundred and seventy one stations recording a total of about 6,000 teleseismic events producing more than 100,000 seismograms have been investigated. The distribution includes 78 stations in the Middle East and Asia, 57 stations in Europe, and 36 stations in central and north Africa. I have examined receiver functions for 119 stations with the best data for the period of 1990-2004 and applied the receiver function stacking procedure of Zhu and Kanamori (2000) to estimate Poisson's ratio and crustal thickness. The research area is divided to five tectonics environments, explicitly Shields, Platform, Paleozoic orogenic belts, Mesozoic-Cenozoic orogenic belts, and rift zones based on Condie's (1989) simplified classifications. The results from this study show a slightly lower value of Poisson's ratio s = 0.25 for Shield compared to the Orogenic-belts with s = 0.26 Crustal thickness H ranges from 32-47 km with an average of 38 km and standard deviation of 3 km for the shields. The less well sampled platforms show a wider distribution of crustal thickness, ranging from 30-58 km with an average 42 km and a standard deviation of 9 km. Orogenic regions also show a wide variation of crustal thickness, with thickness values from 20 to 55 km and standard deviations in the range of 8-10 km. Since the ultimate goal of this study is to provide an improved imaged of global continental structure and composition, I combine observations obtained in this study with receiver functions results from other published analysis. In total, I have integrated observations from 606 stations located in different geologic settings. The compiled results show a value of s = 0.26 for Poisson's ratio and H = 39 km for crustal thickness in Shields and Platforms, and s = 0.26-0.27 with H = 35-37 km for the Orogenic belts. The results show that previously suspected correlations between Poisson's ratio and tectonic age or crustal thickness are more complex - regional variations are more important. Comparison with the standard reference seismic model Crust 2.0 shows that it systematically underestimates crustal shear velocities. A detailed analysis of data from southern Algeria, near the central Hoggar uplift, indicates a significant crustal root beneath the mount Tahat, consistent with underplating of the lower… Advisors/Committee Members: Charles James Ammon, Committee Chair/Co-Chair, Sridhar Anandakrishnan, Committee Member, Kevin Patrick Furlong, Committee Member, Derek Elsworth, Committee Member.

Subjects/Keywords: Crustal thickness; Shear velocity structure; Surface wave dispersion; Receiver functions; Poisson`s ratio

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

APA (6^th Edition):

Kosarian, M. (2008). Lithospheric Structure of North Africa and Western Eurasia . (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/7387

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kosarian, Minoo. “Lithospheric Structure of North Africa and Western Eurasia .” 2008. Thesis, Penn State University. Accessed March 08, 2021. https://submit-etda.libraries.psu.edu/catalog/7387.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kosarian, Minoo. “Lithospheric Structure of North Africa and Western Eurasia .” 2008. Web. 08 Mar 2021.

Vancouver:

Kosarian M. Lithospheric Structure of North Africa and Western Eurasia . [Internet] [Thesis]. Penn State University; 2008. [cited 2021 Mar 08]. Available from: https://submit-etda.libraries.psu.edu/catalog/7387.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kosarian M. Lithospheric Structure of North Africa and Western Eurasia . [Thesis]. Penn State University; 2008. Available from: https://submit-etda.libraries.psu.edu/catalog/7387

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Brno University of Technology

4. Bartoň, Vojtěch. Metodika zkoušek historických cihel a zdiva: Methodology of historical bricks and masonry tests.

Degree: 2020, Brno University of Technology

URL: http://hdl.handle.net/11012/184427

► This diploma thesis is focused on methodology for sorting of solid fired bricks for reconstruction of historical buildings. The theorethical part of this thesis includes… (more)

Subjects/Keywords: mrazuvzdornost; cihla plná pálená; ultrazvuková impulsová metoda; rezonanční metoda; pevnost v tlaku; nedestruktivní zkoušení; malta; Poissonův koeficient; dynamický modul pružnosti; frost resistance; solid fired brick; ultasonic pulse method; resonant frequency method; compressive strength; non-destructive testing; mortar; poisson´s ratio; dynamic modulus of elasticity

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

APA (6^th Edition):

Bartoň, V. (2020). Metodika zkoušek historických cihel a zdiva: Methodology of historical bricks and masonry tests. (Thesis). Brno University of Technology. Retrieved from http://hdl.handle.net/11012/184427

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Bartoň, Vojtěch. “Metodika zkoušek historických cihel a zdiva: Methodology of historical bricks and masonry tests.” 2020. Thesis, Brno University of Technology. Accessed March 08, 2021. http://hdl.handle.net/11012/184427.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Bartoň, Vojtěch. “Metodika zkoušek historických cihel a zdiva: Methodology of historical bricks and masonry tests.” 2020. Web. 08 Mar 2021.

Vancouver:

Bartoň V. Metodika zkoušek historických cihel a zdiva: Methodology of historical bricks and masonry tests. [Internet] [Thesis]. Brno University of Technology; 2020. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/11012/184427.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Bartoň V. Metodika zkoušek historických cihel a zdiva: Methodology of historical bricks and masonry tests. [Thesis]. Brno University of Technology; 2020. Available from: http://hdl.handle.net/11012/184427

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Florida

5. Dunn, Patrick. Comparison of Cone Model and Measured Dynamic Impedance Functions of Shallow Foundations.

Degree: PhD, Civil Engineering - Civil and Coastal Engineering, 2010, University of Florida

URL: https://ufdc.ufl.edu/UFE0041242

► Developments in seismic testing methods and increased electronic recording capabilities have reached a level that allows computation and verification of dynamic impedance function predictions for… (more)

Subjects/Keywords: Damping; Engineering; Footings; Modeling; Parametric models; Poisson ratio; S waves; Stiffness; Velocity; Vibration; cone, dynamic, florida, foundations, functions, geophysical, impedance, measured, model, shallow

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

APA (6^th Edition):

Dunn, P. (2010). Comparison of Cone Model and Measured Dynamic Impedance Functions of Shallow Foundations. (Doctoral Dissertation). University of Florida. Retrieved from https://ufdc.ufl.edu/UFE0041242

Chicago Manual of Style (16^th Edition):

Dunn, Patrick. “Comparison of Cone Model and Measured Dynamic Impedance Functions of Shallow Foundations.” 2010. Doctoral Dissertation, University of Florida. Accessed March 08, 2021. https://ufdc.ufl.edu/UFE0041242.

MLA Handbook (7^th Edition):

Dunn, Patrick. “Comparison of Cone Model and Measured Dynamic Impedance Functions of Shallow Foundations.” 2010. Web. 08 Mar 2021.

Vancouver:

Dunn P. Comparison of Cone Model and Measured Dynamic Impedance Functions of Shallow Foundations. [Internet] [Doctoral dissertation]. University of Florida; 2010. [cited 2021 Mar 08]. Available from: https://ufdc.ufl.edu/UFE0041242.

Council of Science Editors:

Dunn P. Comparison of Cone Model and Measured Dynamic Impedance Functions of Shallow Foundations. [Doctoral Dissertation]. University of Florida; 2010. Available from: https://ufdc.ufl.edu/UFE0041242

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