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Computational mechanics of coherent structural phase transformations.

机译:相干结构相变的计算力学。

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摘要

A methodology for the quantitative analysis of homogeneous nucleation of solid-state phase transformations is developed. At first, a nonlinear nonlocal model based on the stationarity of the Landau-Ginzburg free energy is adopted to study homogeneous nucleation of dilatational and deviatoric (square to rectangular) phase transformations. Although the Landau-Ginzburg approach can span the range from classical to nonclassical nucleation, closed form analytical solutions are not generally feasible. Numerical solutions are obtained via extrema of a perturbed Lagrangian based on the Landau-Ginzburg potential. The weak or variational form of the problem requires ;Another topic of interest is the application of the element-free Galerkin (EFG) method to computational fracture mechanics. Enrichment of the EFG method to incorporate the near-tip singular fields of linear elastic fracture mechanics is introduced. The method is based on enhancement of the basis functions of the EFG method to incorporate the near-tip asymptotic solutions. Numerical examples of stationary linear elastic crack problems in 2D are presented to illustrate the accuracy and effectiveness of the enriched EFC method. Finally, application of the EFG method to the computation of the HRR (power-law plasticity) near-tip fields is presented.
机译:开发了一种定量分析固态相变均匀成核的方法。首先,采用基于Landau-Ginzburg自由能平稳性的非线性非局部模型来研究膨胀形和偏斜(方形到矩形)相变的均质形核。尽管Landau-Ginzburg方法可以涵盖从经典成核到非经典成核的范围,但封闭形式的解析解决方案通常不可行。数值解是根据Landau-Ginzburg势通过摄动的Lagrangian的极值获得的。问题的弱形式或变形式需要;另一个有趣的话题是无元素Galerkin(EFG)方法在计算断裂力学中的应用。介绍了将线性弹性断裂力学的近尖端奇异场纳入其中的EFG方法的扩展。该方法基于对EFG方法基本功能的增强,以合并近端渐近解。给出了二维固定线性弹性裂纹问题的数值示例,以说明富集EFC方法的准确性和有效性。最后,介绍了EFG方法在HRR(幂律可塑性)近尖端场的计算中的应用。

著录项

  • 作者

    Chu, Yi-An.;

  • 作者单位

    Northwestern University.;

  • 授予单位 Northwestern University.;
  • 学科 Materials science.;Mechanics.
  • 学位 Ph.D.
  • 年度 1996
  • 页码 149 p.
  • 总页数 149
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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