NiTi形状记忆合金箱型梁非对称弯曲相变分析

Analysis of Asymmetric Bending Phase Transformation of NiTi Shape Memory Alloy Box Beam

结合已有形状记忆合金材料的本构关系,推导出了形状记忆合金箱型截面梁的非线性控制方程,对箱型截面梁的相变过程进行了力学分析,得出了箱型截面梁的外载荷、拉压不对称系数和箱体厚度对中性轴位移、曲率以及相边界的影响。结果表明:在拉压不对称系数的影响下,需根据箱体厚度与相边界的位置关系,将相变阶段更详细地分步计算;在相同载荷下,箱体厚度增大,中性轴位移明显减小,箱体厚度改变对曲率的最大值影响较大,相边界的位置受箱体厚度的影响明显。

The non-linear control equations of the box shaped memory alloy beam are derived by combining the existing constitutive relation of shape memory alloy materials,and the mechanical analysis of the phase transformation process of the box-shaped cross-section beam is carried out,and the effects of the external load,the tension-compression asymmetry coefficient,and box thickness on the neutral axis displacement,curvature and phase boundary of the box-shaped cross-section beam are derived.Under the influence of the tension-compression asymmetry coefficient,the phase transformation process needs to be calculated in more detail in steps depending on the position of the box thickness in relation to the phase boundary.The results show that the displacement of the neutral axis decreases significantly with increasing thickness of the box under the same load.The change of box thickness has a greater effect on the maximum value of curvature and the position of the phase boundary is significantly influenced by the box thickness.