Dissertation
QUASI-STATIC AND DYNAMIC DEFORMATION AND FRACTURE OF A THERMOPLASTIC ELASTOMER TISSUE SURROGATE: EXPERIMENTS AND MODELING BY A VISCO-PSEUDO-HYPERELASTIC MODEL
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004396
Handle:
https://hdl.handle.net/2376/125467
Abstract
Characterization and modeling of the mechanical behavior of biological tissues are critical to many biomedical related applications. For research and development, various soft materials have often been used as a tissue substitute. Among them, the mineral oil-based synthetic polymer styrene-ethylene-butylene-styrene (SEBS) gel has gained some popularity due to its superior mechanical and physical properties. Tissue materials or their simulants are often characterized with quasi-static loading and are treated and modeled as a nonlinear hyperelastic material. As tissues are often subjected to loadings with a wide range of strain rates, understanding of the mechanical behavior and development of a predictive capability for such loadings are essential. The objectives of this study are two-folds. One is to experimentally characterize the deformation and fracture behaviors of SEBS gels with different chemical compositions and polymer concentrations under uniaxial loadings with a wide range of strain rates, and the other is to develop a material model that is viable for such loadings.
For charactering the deformation behavior, the quasi-static loading experiments were conducted with standard mechanical test system and the dynamic loading experiments were conducted with the Split Hopkinson Pressure Bar (SHPB) technique. The strain rates ranged from 1×10-3/s to 6×103/s. The fracture behavior was characterized with two types of experiments, namely, pure shear test and trouser test, with strain rates in the range of 1×10-3/s~1×10-1/s. The two types of tests yielded consistent results. Both deformation and fracture behaviors exhibited substantial rate sensitivity.
Based on the data from deformation characterization, a comprehensive visco-pseudo-hyperelasticity model was developed. The model was demonstrated to be able to capture all the material features observed in the experiments, such as rate sensitivity, strain-induced softening, and permanent deformation after unloading. The developed model was then used to determine the fracture toughness and gain insights on the rate dependence of the fracture behavior of SEBS gel.
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Details
- Title
- QUASI-STATIC AND DYNAMIC DEFORMATION AND FRACTURE OF A THERMOPLASTIC ELASTOMER TISSUE SURROGATE
- Creators
- Yao Chen
- Contributors
- Jow-Lian Ding (Advisor)Jinwen Zhang (Committee Member)Kuen-Ren (Roland) Chen (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- School of Mechanical and Materials Engineering
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 147
- Identifiers
- 99900883137001842
- Language
- English
- Resource Type
- Dissertation