形状记忆合金耗能弹簧的力学性能研究

INVESTIGATION OF MECHANICAL FEATURES OF ENERGY DISSIPATION SPRING MADE OF SHAPE MEMORY ALLOY

从Helmholt自由能出发,建立了SMA材料在复杂应力状态下的热力学本构关系,并由此推导出SMA耗能弹簧的热力学本构关系;在Brinson相变发展方程的基础上,引入等效应力的概念后,建立了内变量马氏体百分数的发展方程。利用上述理论,结合普通金属弹簧的设计方法,建立了SMA耗能弹簧的设计方法;利用MATLAB编写的计算机程序进行了仿真计算。研究结果表明SMA耗能弹簧具有较好的耗能能力。本文建立的计算理论较好地吻合了其他学者的研究结果,适用于实际工程问题的理论分析,具有较大的适用价值。

A thermodynamical constitutive model of the shape memory alloy (SMA for short) under the complex stress state is established based on Helmholt free energy. The thermodynamical constitutive model of an energy dissipation spring made of SMA is also established based on this model. With the Brinson's phase transformation equation, the development equations of inner variable about martensite percentage of the spring are given after introducing the concept of equivalent stress. A design method for the energy dissipation spring made of SMA is recommended combining the design method of common spring. The numerical calculation is carried out by utilizing MATLAB program developed by the authors. The investigation result indicates that the energy dissipation spring made of SMA has better capacity of energy dissipation. The theory presented agrees preferably with the results of other researchers.