考虑残余变形的SMA棒材数值模拟方法研究

Study on numerical simulation method of SMA bars considering residual deformation

为了模拟实际情况中超弹性形状记忆合金(shape memory alloy,SMA)棒材在循环拉伸荷载作用下的残余应变,解决SMA棒材在自复位体系中应用时结构的自复位性能数值模拟结果偏于理想的问题,提出了一种可以考虑残余变形的SMA棒材数值模拟方法。采用基于唯象理论的Auricchio本构模型,对4个超弹性SMA棒材算例进行有限元模拟,在此基础上,采用材料置换的思路,以等效弹塑性金属的塑性变形来反映SMA棒材受力后的残余变形,给出了具体的SMA棒材残余变形有限元模拟方法,并根据试验数据对模拟结果进行了验证。研究结果表明,基于Auricchio本构模型的SMA棒材有限元模拟结果无法表现材料的残余变形,而采用所提出的可以考虑残余变形的SMA棒材数值模拟方法能够较好地反映SMA棒材包括残余应变在内的各项力学性能。

To simulate the subsistent residual strain of superelastic shape memory alloy(SMA)bars under cyclic tensile load,and solve the problem that the numerical simulation results of self-centering performance of the structure with SMA bars are too ideal,a numerical simulation method of SMA bars considering residual deformation is proposed.The phenomenological Auricchio constitutive model was used to simulate four superelastic SMA bars in different tests.The plastic deformation of equivalent elastoplastic metal was used to reflect the residual deformation of SMA bars by the method of material replacement.On this basis,the finite element method for simulating residual deformation of SMA bars was proposed,and the simulation results were verified according to experimental data.The simulation results show that the built-in Auricchio constitutive model cannot simulate the residual deformation of SMA bars,while the proposed numerical simulation method considering residual deformation can well reflect the mechanical properties of SMA bars including residual strain.