不同材料模型的超弹TiNi合金法向接触的有限元分析

FEM analysis of pseudoelastic TiNi alloy under normal contact using two material models

采用多线性弹性和双线性等向强化两种材料模型 ,对在法向力载荷作用下的TiNi形状记忆合金进行有限元模拟。结果表明 :多线性弹性模型不适合用来分析TiNi合金的超弹性 ;而通过用最大弹性变形量 (与屈服极限对应的极限应变值 )来模拟TiNi合金的超弹性 ,采用双线性等向强化模型可以描述TiNi合金的超弹性与产生的最大VonMises弹性应变及最大VonMises塑性应变之间的关系 ,能够为以TiNi合金作为机敏材料、耐磨材料及耐磨膜层材料设计提供依据。最后 ,在该材料模型下 ,将用有限元方法与用纳米力学探针得到的位移与载荷关系曲线进行对比 。

Two different material models(mutilinear elastic mode l and bilinear isotropic hardening model) were used to carry out the finite elemen t analysis of TiNi shape memory alloy with pseudoelasticity feature under normal force load. The results show that the mutilinear elastic model is not appropria te for analyzing the pseudoelasticity of TiNi alloy, but through using the maxim um elastic deformation (the strain value at the yield point) to simulate the pse udoelasticity of TiNi shape memory alloy, the bilinear isotropic hardening model can describe the relationships between the pseudoelasticity of TiNi shape memor y alloys and strains including elastic strain and plastic strain. The results go tten from this analysis using the bilinear isotropic hardening model can be used to provide the reference for designing TiNi alloy as smart material and anti-w ear material. Finally, under the bilinear isotropic hardening model, the relatio nship between load and displacement gotten from FEM was compared with that deriv ed from nanoindenter, results indicate that they are at close range.