A Mico-Mechanics Based Thermo-Mechanica Constitutive Model for Finite Deformation Analysis of Shape Memory Materials

*CMS-9813386Masd发展了一种新的非弹性模型的内变量形式，该模型能够表示超弹性相变和完全耦合的热力相变是形状记忆合金。这些模型能反映不同材料在拉伸和压缩下的响应，并能考虑单变量马氏体重取向过程。通过采用变形梯度的乘法分裂，将本构模型推广到有限变形区域。讨论了形状记忆合金中多种自然构型引起的对称性群的变化问题。本文发展了一个无条件稳定的算法来求解SMA的完全热力耦合系统，详细讨论了通过返回映射格式对本构方程进行数值积分的技术问题，以及实现高阶收敛所需的算法一致性切线的形式。

***CMS-9813386MasudAn internal-variable formalism is developed for a new family of inelastic models that are capable of representing the super-elastic transformations as well as the fully coupled thermo-mechanical phase transformarion is Shape Memory Alloys. These models can show different material response in tension and compression, and can account fof th single-variant-martensite reorientation prcess. The constitutive models are extended to the finite deformation regime by employing a multiplicative split of the deformation gradient. The issue of change in symmetry group because of the multiple natural configurations in SMA's is addressed. An unconditionally stable algorithm is develloped to solve the completed coupled thermo-mechanical system arising is SMA's. Technical issues related to numerical integration of the constitutive equations via the return mapping schemes, and the form of algorithmically consistent tangents needed to achieve higher order convergence are addressed in detail.***