Abstract A crystal plasticity finite element (CPFE) model is developed for pseudoelastic NiTi shape memory alloy (SMA). The model includes various inelastic mechanisms of deformation such as martensite transformation, dislocation glide in austenite phase and twinning in the martensite phase. This model is based on the finite deformation theory and predicts phase transformation, stress field and residual strain due to slip and twinning. Following the work of Anand and Gurtin (2003), the Helmholtz free energy is derived and further the thermodynamic driving forces for slip, twin and phase transformation are obtained by using Clausius-Duhem inequality. The developed constitutive model has been implemented within a user material subroutine interface VUMAT in ABAQUS™/Explicit. The activation of different inelasticity mechanisms at different temperatures and strains are first verified by performing various simulations of uniaxial tensile deformation. Then the model is calibrated and validated against the experimental stress-strain response of NiTi single crystal as reported in the literature. The single crystal constitutive model is extended for modeling the response of a polycrystal with both initial random and textured crystallographic orientations using Taylor scale transition technique. A series of simulations are performed on polycrystalline representative volume element (RVE) at various temperatures and strains. The effect of temperature and imposed strain on phase transformation and residual strain is investigated systematically. The residual strain increases due to slip in austenite phase and twinning in the martensite phases that are activated as temperature and imposed strain increase respectively. Further the uniaxial loading conditions are extended to multiaxial loading and the results are compared against the experimental data.

中文翻译：

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考虑各种非弹性机制的伪弹性NiTi形状记忆合金有限变形建模

摘要 建立了伪弹性NiTi形状记忆合金(SMA)的晶体塑性有限元(CPFE)模型。该模型包括各种非弹性变形机制，例如马氏体相变、奥氏体相中的位错滑移和马氏体相中的孪晶。该模型基于有限变形理论，可预测由于滑移和孪晶引起的相变、应力场和残余应变。根据 Anand 和 Gurtin (2003) 的工作，导出了亥姆霍兹自由能，并进一步通过使用克劳修斯-杜亨不等式获得了滑移、孪晶和相变的热力学驱动力。开发的本构模型已在 ABAQUS™/Explicit 中的用户材料子程序接口 VUMAT 中实现。首先通过对单轴拉伸变形进行各种模拟来验证不同温度和应变下不同非弹性机制的激活。然后根据文献中报道的 NiTi 单晶的实验应力应变响应校准和验证模型。扩展了单晶本构模型，以使用泰勒标度转换技术对具有初始随机和纹理晶体取向的多晶的响应进行建模。在不同温度和应变下对多晶代表性体积单元 (RVE) 进行了一系列模拟。系统地研究了温度和外加应变对相变和残余应变的影响。残余应变由于奥氏体相中的滑移和马氏体相中的孪晶而增加，它们分别随着温度和外加应变的增加而激活。此外，单轴加载条件扩展到多轴加载，并将结果与​​实验数据进行比较。