基于改进相变方程的形状记忆合金弹性耦合系统特性分析  

Characteristics Analysis of Shape Memory Alloy Elastic Coupling System Based on Improved Phase Transformation Equation

作　　者：朱孙科[1] 闵旭 董绍江[1] ZHU Sunke;MIN Xu;DONG Shaojiang(School of Mechanotronics and Vehicle Engineering,Chongqing Jiaotong University,Chongqing 400074)

机构地区：[1]重庆交通大学机电与车辆工程学院,重庆400074

出　　处：《机械工程学报》2024年第14期194-205,共12页Journal of Mechanical Engineering

基　　金：重庆市科技创新领军人才支持计划资助项目(CSTCCCXLJRC201920)。

摘　　要：为准确描述形状记忆合金(Shape memory alloy,SMA)弹性耦合系统的驱动特性,考虑模型复杂程度与工程实际需求,提出了一种基于Brinson本构方程和SMA相变原理的改进相变模型。针对Brinson相变模型SMA马氏体正相变过程中马氏体分数不连续的问题,将孪晶马氏体相转化为孪晶马氏体相和非孪晶马氏体相相混合相终点时各晶体体积分数,作为马氏体正相变终点时的晶体体积分数,视马氏体正相变为一个连续的过程,对原Brinson相变模型中马氏体正相变方程进行修正。以偏置式SMA丝驱动器为研究对象,建立了SMA弹性耦合系统模型,采用改进的Brinson相变模型分别对具有不同偏置弹簧的系统进行仿真分析,并与相应试验结果比较。结果表明,改进相变模型的计算结果与试验吻合较好,且在相变过程中马氏体相和奥氏体相体积分数和为1,符合实际情况。分析发现,对于SMA弹性耦合系统,偏置弹簧的刚度越大,驱动器响应速度越慢,相变温度区间和完全马氏体逆相变所需的加热电流越大,驱动应变先增加后减小。研究结果可更准确地描述SMA驱动器的作动过程,为偏置式SMA丝驱动器的设计提供参考。An improved phase transformation model based on the Brinson constitutive equation and the phase transformation principle of shape memory alloy(SMA)is proposed in order to accurately describe the actuating characteristics of SMA elastic coupling system,considering the complexity of the model and actual engineering requirements.A discontinuous problem of martensite fraction during the martensitic transformation in the positive phase transformation process of the Brinson phase transformation model is addressed.The twin martensite phase is transformed into a mixture of twin martensite phase and non-twin martensite phase at the end point of the phase transformation,and the volume fractions of each crystal at this point are considered as the crystal volume fractions at the end point of the positive phase transformation of martensite.The positive phase transformation of martensite is treated as a continuous process,and the equation for the positive phase transformation of martensite in the original Brinson phase transformation model is modified.A SMA elastic coupling system model is established based on a biased SMA wire actuator,and the improved Brinson phase transformation model is used to simulate and analyze system with different biased springs.The simulation results are compared with the corresponding experimental results.The results show that the computation results of the improved phase transformation model are in good agreement with the experimental results,and the volume fractions of martensite and austenite sum up to 1 during the phase transformation process,which is consistent with the actual situation.The analysis reveals that for SMA elastic coupling system,a larger stiffness of the bias spring leads to a slower response speed of the actuator,a wider temperature range for the phase transformation,and a higher heating current required for the complete martensite reverse phase transformation.The actuating strain initially increases and then decreases.The research results can more accurately describe the actua

关 键 词：形状记忆合金 驱动特性 相变方程 偏置弹簧 

分 类 号：TB381[一般工业技术—材料科学与工程]