中文摘要：

通过拉伸试验,研究了超弹性形状记忆合金（SMA）丝在不同应变幅值反复加卸载条件下的滞回变形行为。在测得试验数据的基础上,针对目前广泛使用的SMA Graesser＆Cozzarelli模型仅描述了小应变情况下SMA特性,而在大应变下SMA马氏体的硬化特性不能得到描述的问题,提出了修正的SMA本构模型,并把模型拟合结果和实验数据进行了比较分析。结果表明,模型数值拟合结果和试验数据吻合很好,可以很好地描述SMA在不同应变幅值下的应力-应变关系;且模型形式简单,概念明确,参数容易得到,具有一定的工程应用价值。

英文摘要：

In this paper,the superelastic deformation behavior of the NiTi shape memory alloy wires subjected to cyclic loading under variable amplitudes is investigated experimentally.According to the test data,a constitutive model for the shape memory alloys is presented based on the Graesser＆Cozzarelli model that is a widely-used model of SMA hysteresis behavior for seismic applications,which captures the characteristics under small amplitudes but does not include the martensitic hardening characteristic of SMA under amplitudes.Then,a comparison of the numerical results with the extended model to experimental data is given,which shows good agreement and verifies that the model is able to satisfactorily predict the response of SMA under variable amplitudes.Also,with simple formulation,definite concept and easily obtained parameters,the model is useful for practical engineering application of SMA.