<p> Bi<sub>2</sub>Sr<sub>2</sub>CaCu<sub>2</sub>Ox (Bi2212) superconducting round wires are a well-known high temperature superconductor due to their isotropic properties, high fill factor, and ease of winding. There have been extensive experiments to improve the wires’ performance, yet there is little understanding of how the internal microstructure of the wires influences the mechanical behavior. This is due to the multiple phases and their complex arrangements inside the wires, making it challenging for traditional approaches to investigate and simulate the wires’ behavior. The peridynamic theory, using non-local interactions and integral constitutive equations, can provide a solution to these challenges from the Bi2212 wires microstructure. To reduce computation cost, in this study the peridynamic formulas are developed for 2D simulations. Dynamic relaxation and energy minimization methods to find the steady-state solution are used and compared. The model shows m-convergence and δ-convergence behaviors when m increases and ä decreases. Model verification shows close quantitative matching to finite element analysis results. The 2D peridynamic model is then used to simulate mechanical behavior of Bi2212 wires. Various types of natural and artificial defects are simulated and compared quantitatively. Both defect geometry and physical characteristics are investigated to study their influence on the stress concentration in the material. The results show significant stress concentration around defects and protruding growths of the Bi2212 phase.</p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:3584007 |
| Date | 20 August 2014 |
| Creators | Le, Quang Van |
| Publisher | North Carolina State University |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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