功能梯度形状记忆合金细观力学本构模型

功能梯度形状记忆合金(Functionally Graded Shape Memory Alloy, 简称FG-SMA)是一种新型功能梯度复合材料, 它兼备功能梯度材料和形状记忆合金(Shape Memory Alloy)两种材料的优异特性。该文根据细观力学的理论, 考虑材料的微观组成及相互作用, 建立了一个适合于描述FG-SMA材料力学性能的细观力学本构模型, 该模型可以准确的描述复杂载荷作用下FG-SMA的力学行为。应用这个模型, 该文详细分析了一个由弹性材料和SMA组成的FG-SMA梁在轴力和弯矩共同作用下的受力变形行为。由数值算例可知, 这种新型材料可显著减小载荷作用下的最大应力, 避免材料由于应力过大而导致的破坏。此外, FG-SMA还具有一些其它独特的性能, 可满足实际应用中一些特殊的需要。该文的研究结果可为该类材料的进一步研究提供基础, 为该类材料的应用提供依据。

A MICROMECHANICAL MODEL FOR THE FUNCTIONALLY GRADED SHAPE MEMORY ALLOY

The Functionally Graded Shape Memory Alloy (FG-SMA) is a new kind of functionally graded composite which possesses the excellent properties of both functionally graded materials and Shape Memory Alloys (SMA). Based on the theory of micromechanics, a constitutive model for this new material is established, considering the microstructure of the material. This model can describe the mechanical behavior of the FG-SMA under complex loads accurately. With this model, a FG-SMA beam composed by elastic material and SMA subjected to an axial force and a bending moment is investigated in detail. It can be concluded from the numerical results that FG-SMA can decrease the maximum stress efficiently, preventing the destruction caused by oversize stress. Several other particular features of this new material are also observed, which will content many special requirements in practice applications. This research can provide a base for the in-depth investigation of FG-SMA material.