作者: Patrick Werner Dondl
DOI: 10.7907/89AW-3S87.
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摘要: This work examines two major aspects of martensitic phase boundaries. The first part studies numerically the deformation thin films shape memory alloys by using subdivision surfaces for discretization. These have gained interest their possible use as actuators in microscale electro-mechanical systems, specifically a pyramid-shaped configuration. study such configurations requires adequate resolution regions high strain gradient that emerge from interplay multi-well energy and penalization through surface term. term also spatial numerical discretization to be higher regularity, i.e., it needs continuously differentiable. excludes piecewise linear approximation. It is shown this thesis provide an attractive tool examination transforming structures. We insight properties tent-like structures. The second question how rate-independent hysteresis observed transformations can reconciled with kinetic relation linking evolution domains thermodynamic driving force on microscopic scale. A sharp interface model boundaries, including full elasticity, proposed. existence solution coupled problem free discontinuity elliptic equation proved. Numerical show pinning boundary precipitates non-transforming material. step stick-slip behavior therefore hysteresis. In approximate model, critical well solutions traveling average velocity are proved rigorously. For shallow approximation, depinning studied numerically. find universal power-law interface. smooth local due inhomogeneous but periodic environment we exponent 1/2.