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You searched for +publisher:"University of Illinois – Urbana-Champaign" +contributor:("Little, Dallas"). Showing records 1 – 2 of 2 total matches.

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University of Illinois – Urbana-Champaign

1. Hernandez, Jaime Alberto. Development of deformable tire-pavement interaction: contact stresses and rolling resistance prediction under various driving conditions.

Degree: PhD, Civil Engineering, 2015, University of Illinois – Urbana-Champaign

Even though continuous improvements have been seen in the analysis of flexible pavements, one of the most important factors is still oversimplified: the tire. This can result in costly decisions, such as poor structural road design, incorrect damage prediction, and inappropriate adoption of maintenance/rehabilitation techniques. Moreover, accurate analysis of the tire-pavement system improves predictions of rolling resistance, fuel consumption, and greenhouse gas emissions. The main contribution of this research lies in the evaluation of tire and pavement as a semi-coupled system, assuming both are deformable bodies, while focusing on contact stresses, rolling resistance, and pavement responses. In addition to load and tire inflation pressure, temperature, speed, and rolling conditions were considered. A series of necessary advancements in the tire model, such as appropriate material characterization (hyperelastic and visco-hyperelastic), accurate geometry, and model validation using experimental measurements, were implemented. The experimental program provided information for validation (contact area, tire deflection, and contact stresses/loads). In addition, based on the experimental measurements, a procedure including analytical expression was proposed to predict the variation of the vertical and transverse contact loads along the contact length. Four tire finite element (FE) models having accurate geometry and material characterization were developed to predict contact stresses and rolling resistance force. First, a hyperelastic tire was used on a rigid surface to predict contact stresses under various rolling and loading conditions. Second, the influence of tire speed and temperature was investigated using a visco-hyperelastic tire rolling on rigid surface. Third, hyperelastic tire on deformable elastic body was used to assess the sensitivity of the contact stresses to the body's stiffness. Fourth, the relevance of surface temperature and tire speed was determined using a hyperelastic tire on a deformable viscoelastic body. Finally, the deformable tire and pavement model were integrated to evaluate critical pavement responses, rolling resistance force, and structure-induced rolling resistance. Vertical and transverse contact loads for all conditions and longitudinal contact stresses at full braking were successfully fitted to analytical expressions, thus easing their potential application in pavement analysis. Based on the hyperelastic tire FE results, the vertical contact stresses were unaffected by traveling speed and rolling condition, and the rolling condition mainly modified the longitudinal contact stresses. After altering the rubber component’s material model to visco-hyperelastic, the contact area increased 6.8% due to temperature and decreased 3.8% due to speed. In addition, longitudinal contact stresses were the most affected by temperature and speed: increments in peak value caused by speed were as high as 17%, and the reduction caused by temperature reached 33.1%. On the other hand,… Advisors/Committee Members: Al-Qadi, Imad L (advisor), Al-Qadi, Imad L (Committee Chair), Little, Dallas (committee member), Masud, Arif (committee member), Ozer, Hasan (committee member), Radulescu, Robert (committee member), Thompson, Marshall (committee member).

Subjects/Keywords: Tire-pavement interaction; pavement responses; rolling resistance; contact stresses; finite element modeling

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

APA (6th Edition):

Hernandez, J. A. (2015). Development of deformable tire-pavement interaction: contact stresses and rolling resistance prediction under various driving conditions. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/89127

Chicago Manual of Style (16th Edition):

Hernandez, Jaime Alberto. “Development of deformable tire-pavement interaction: contact stresses and rolling resistance prediction under various driving conditions.” 2015. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 20, 2021. http://hdl.handle.net/2142/89127.

MLA Handbook (7th Edition):

Hernandez, Jaime Alberto. “Development of deformable tire-pavement interaction: contact stresses and rolling resistance prediction under various driving conditions.” 2015. Web. 20 Jan 2021.

Vancouver:

Hernandez JA. Development of deformable tire-pavement interaction: contact stresses and rolling resistance prediction under various driving conditions. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2015. [cited 2021 Jan 20]. Available from: http://hdl.handle.net/2142/89127.

Council of Science Editors:

Hernandez JA. Development of deformable tire-pavement interaction: contact stresses and rolling resistance prediction under various driving conditions. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2015. Available from: http://hdl.handle.net/2142/89127

2. Ozer, Hasan. Development of domain integral and generalized finite element methods for three dimensional analysis of near-surface cracking in flexible pavements.

Degree: PhD, 0106, 2011, University of Illinois – Urbana-Champaign

Layered elastic theories and finite element method are among the most familiar and practiced mechanistic approaches. These approaches succeed to a certain extent in the analysis of classical bottom-up fatigue cracking of relatively thin flexible pavements, where tensile stresses and strains govern the behavior at the asphalt layer. However, elastic theories are incapable of predicting other pavement distresses, including near-surface cracking. Similarly, finite element method, which is equipped with fracture and continuum mechanics theories, also poses a significant challenge to the analysis of the near-surface cracking problem, where crack initiation and propagation planes are not easily predictable. Hence, the main objective of this study is to identify the effect of loading tire contact stresses on developing near-surface cracking potential. A numerical approach is chosen to analyze the problem, taking into account considering nonuniform tire-pavement contact stresses and multi-axial stress states in the proximity of tires. This study highlights the impact of novel computational methods, such as the Generalized Finite Element Method (GFEM), on the discovery and understanding of cracking mechanisms in pavements. GFEM allows for realistic modeling of complex phenomena that control fracture initiation and propagation. In this study, GFEM is adapted to analyze relatively thick flexible pavement structures to predict near-surface cracking. The three-dimensional (3-D) and highly multi-axial nature of the problem is successfully captured by this method, which is ideally designed for 3-D fracture problems for complex geometries and mixed loading conditions. This study proposes a high-order domain integral method for the computation of the crack front parameters such as energy release rate and stress intensity factors (SIFs). The method provides an approximation of the energy release rate function as a linear combination of Legendre polynomials. As a result, extracted functions are smoothly varying, which is crucial to obtain accurate crack propagation paths in 3-D for elastic or inelastic materials. Crack front directionality is captured by the proposed formulations and implementation using an energy release rate-based approach. The study also applies for the first time the domain integral techniques to pavement fracture problems utilizing the asphalt concrete viscoelastic characteristics. The GFEM, equipped with the tools developed in this study, is used as a computational platform to analyze near-surface cracking in relatively thick flexible pavement structures. Three-dimensional models of typical pavement structures are developed to analyze near-surface cracking and make predictions for potential critical locations for crack initiation and growth. Two potential scenarios become evident for crack growth in the vicinity of tires: Shear crack under compression and tensile crack. It is observed from the analysis that shear crack growth is the dominant mode of crack development due to loading in the proximity of tires,… Advisors/Committee Members: Al-Qadi, Imad L. (advisor), Al-Qadi, Imad L. (Committee Chair), Duarte, C. Armando (Committee Chair), Buttlar, William G. (committee member), Little, Dallas N. (committee member), Roesler, Jeffery R. (committee member).

Subjects/Keywords: Generalized Finite Element Method (GFEM); pavements; fracture; tires

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

APA (6th Edition):

Ozer, H. (2011). Development of domain integral and generalized finite element methods for three dimensional analysis of near-surface cracking in flexible pavements. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/24268

Chicago Manual of Style (16th Edition):

Ozer, Hasan. “Development of domain integral and generalized finite element methods for three dimensional analysis of near-surface cracking in flexible pavements.” 2011. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 20, 2021. http://hdl.handle.net/2142/24268.

MLA Handbook (7th Edition):

Ozer, Hasan. “Development of domain integral and generalized finite element methods for three dimensional analysis of near-surface cracking in flexible pavements.” 2011. Web. 20 Jan 2021.

Vancouver:

Ozer H. Development of domain integral and generalized finite element methods for three dimensional analysis of near-surface cracking in flexible pavements. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2011. [cited 2021 Jan 20]. Available from: http://hdl.handle.net/2142/24268.

Council of Science Editors:

Ozer H. Development of domain integral and generalized finite element methods for three dimensional analysis of near-surface cracking in flexible pavements. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2011. Available from: http://hdl.handle.net/2142/24268

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