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Experimental Studies and Multi-Scale Modelling of Advanced Ceramics: Fracture, Fragmentation, and Failure
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- Author / Creator
- Zheng, Jie
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The objectives of this thesis is to explores the mechanical behaviour of alumina ceramics, focusing on fracture and fragmentation response through a blend of experimental investigations and advanced computational modelling. To bridge the gap between micro-mechanisms and macroscopic material behaviors, the microstructure and mechanical properties of the CeramTec ALOTEC 98 SB (CeramTec 98\%) alumina ceramic are examined using microscopic characterization and mechanical testing under various strain-rate and stress-state loading conditions. The mechanical tests employs a modified split-Hopkinson pressure bar complemented by high-speed imaging and digital image correlation (DIC), to capture the fracture processes and stress fields. The testing results indicate that this ceramic exhibits superior mechanical properties to other commercial alumina ceramics, with strengths becoming stronger with higher strain rates. Further, a three-dimensional hybrid finite-discrete element model considering the flaw system of advanced ceramics is developed and validated against experimental data. These models successfully simulated crack initiation, propagation, and fragmentation processes, offering new perspectives on the failure process of alumina ceramics. Sensitivity analyses explore the influence of material properties, such as elastic modulus, fracture properties and flaws, on mechanical strength, including the tensile and compressive strength of advanced ceramics. By integrating experimental and computational approaches, this research advances the fundamental understanding of failure mechanisms of alumina ceramics. The findings provide valuable insights into the design and optimization of advanced ceramics, contributing to the development of next-generation advanced ceramic materials for defence and aerospace applications.
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- Graduation date
- Fall 2024
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.