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A continuum sensitivity analysis of large deformations with applications to metal forming process design.

机译：大变形的连续性敏感性分析及其在金属成形工艺设计中的应用。

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摘要

A continuum sensitivity analysis is presented for the evaluation of parameter and shape sensitivities of large hyperelastic-viscoplastic deformations of isotropic materials involving contact with friction using a direct differentiation method. The sensitivity formulation is based on the design differentiation of the governing field equations of the direct deformation problem at the continuum level and a weak form for the sensitivity equilibrium equation is developed. This sensitivity weak form is linearly coupled with the appropriate sensitivity contact and sensitivity constitutive problems. To avoid issues related to the non-differentiablity of contact conditions, regularizing assumptions are introduced for the computation of traction sensitivities. The sensitivity weak form is modified for the consistent finite element treatment of near-incompressibility within the context of the assumed strain methods. The sensitivity analysis is derived within a total Lagrangian as well an updated Lagrangian framework. The updated Lagrangian sensitivity analysis is appropriate when remeshing operations are performed in the direct deformation problem to avoid the excessive distortions that result in Lagrangian finite element formulations. A method is also proposed for the transfer of design sensitivities between meshes. The results of the continuum sensitivity analysis are used to compute design gradients of the objective function and constraints in an appropriately selected finite dimensional design space, in order to solve selective design problems in metal forming. This work on the design of single-stage forming processes is expanded to include the preliminary design of multi-stage forming processes.
机译：提出了一种连续敏感度分析，用于使用直接微分方法评估各向同性材料涉及摩擦接触的大的超弹性-粘塑性变形的参数和形状敏感性。灵敏度公式是基于连续变形水平上直接变形问题的控制场方程的设计微分，并为灵敏度平衡方程开发了一种弱形式。这种敏感性弱形式与适当的敏感性接触和敏感性本构问题线性耦合。为了避免与接触条件的不可区分性相关的问题，引入正则化假设以计算牵引力敏感性。在假定的应变方法的范围内，修改了灵敏度弱形式，以对近不可压缩性进行一致的有限元处理。敏感性分析是在总的拉格朗日和更新的拉格朗日框架内得出的。更新的拉格朗日灵敏度分析适用于在直接变形问题中执行重新网格化操作，以避免导致拉格朗日有限元公式化的过度变形。还提出了一种在网格之间传递设计敏感性的方法。连续性敏感性分析的结果用于在适当选择的有限尺寸设计空间中计算目标函数和约束条件的设计梯度，以解决金属成型中的选择性设计问题。有关单阶段成型工艺设计的工作已扩展到包括多阶段成型工艺的初步设计。

著录项

  • 作者

    Akkaram, Srikanth.;

  • 作者单位

    Cornell University.;

  • 授予单位 Cornell University.;
  • 学科 Engineering Mechanical.; Applied Mechanics.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 196 p.
  • 总页数 196
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;应用力学;
  • 关键词

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