形状记忆合金本构模型的热力学框架

A thermodynamics framework for constitutive models for shape memory alloys

基于形状记忆合金(SMAs)在相变过程中的热力学势和能量耗散来建立形状记忆合金的本构模型框架,通过采用不同独立变量(应力、应变、温度和熵)的组合来选择不同的能量函数(内能、Helmholtz自由能、Gibbs自由能和焓),用内状态变量考虑相变过程中的能量耗散,则SMAs的本构模型完全可以由热力学势及能量耗散函数来建立,实例表明其可行性.

An incremental formulation of the shape memory alloys (SMAs) is described based on the use of thermodynamic potentials. The four energy functions commonly used in thermodynamics (internal energy, Helmholtz free energy, enthalpy and Gibbs free energy) are used to provide the descriptions depending on the conditions that the combinations of the stress, strain, temperature and entropy are taken as the independent variables. The dissipative behavior is introduced through the use of internal parameters. The constitutive behavior is entirely determined by the knowledge of two scalarpotentials. The examples show its feasibility.