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形状记忆合金(SMA)是一种兼具感知和驱动功能的功能材料,因其独特的形状记忆效应、超弹性和高阻尼等特性,成为土木工程结构振动控制的理想材料.论文研究了超弹性NiTi丝的动力特性和应变率相关的本构模型.试验测试了NiTi丝在不同应变率下的力学性能,建立了应力增量与应变率的关系方程.在试验的基础上,提出了改进的SMA本构模型,新模型能够描述SMA应变率相关特性,并通过仿真结果和试验结果的比较,验证模型的正确性和适用性.研究结果表明:动力荷载下,NiTi丝每循环耗散能量、割线刚度和等效阻尼比在开始阶段均快速增大,当应变速率大于1.0×10-3/s后,趋于平缓;数值结果和试验结果吻合较好,改进模型在一定程度上可以描述NiTi丝应变率相关的动力特性.
Shape memory alloy (SMA) is a kind of functional material with both sensing and driving functions, and it has become an ideal material for structural vibration control of civil engineering because of its unique shape memory effect, super-elasticity and high damping properties.In this paper, NiTi wire dynamic properties and strain rate of the constitutive model.This experiment tested the mechanical properties of NiTi wire at different strain rates and established the relationship between stress increment and strain rate equation.On the basis of the experiment, SMA constitutive model, the new model can describe the SMA strain rate-related characteristics and verify the correctness and applicability of the model by comparing the simulation results with the experimental results.The results show that: NiTi wire dissipates energy per cycle under dynamic load, The secant stiffness and equivalent damping ratio increase rapidly in the initial stage, and tend to be gentle when the strain rate is greater than 1.0 × 10-3 / s. The numerical results are in good agreement with the experimental results. The improved model can be described to some extent Dynamic Properties Related to NiTi Wire Strain Rate.