记忆合金/Si复合膜驱动性能的力学建模与仿真

Modeling and Simulation on the Actuation Performance of Shape Memory Alloy/Si Composite Diaphragm

在考虑记忆合金材料非线性的基础上,按照材料力学的方法联立静力学、变形几何及物理的三者关系,建立了热载荷作用下记忆合金薄膜与Si基底相互耦合作用的力学模型.通过对一个完整的热循环过程中NiTi记忆合金/Si复合膜驱动性能的模拟和讨论,结果表明,由于相变的作用,以Si为基底的记忆合金薄膜能在较窄的温度范围内产生大的驱动力及位移.通过对不同厚度比情况下复合膜最大挠度的研究发现,随着Si基底与记忆合金薄膜厚度比的增大,复合膜的最大挠度逐渐减小;当两者厚度比大于5时,本模型对记忆合金/Si复合膜驱动性能的描述和预测更精确.

The mechanical model of shape memory alloy composite diaphragm based on Si substrate was established by combining static equilibrium equations,geometric equation and physical equations by the method of the mechanics of materials to consider the coupled action between the shape memory alloy and Si substrate under thermal loads.The material nonlinearity of the shape memory alloy film is also considered.The actuation performances of the SMA composite diaphragm were simulated and discussed for one whole thermal loading cycle,which verifies that large actuation forces and displacements can be produced in a narrow temperature range due to the phase transformations of shape memory alloys.Additionally,the maximum deflection of the composite diaphragm varying with the thickness ratios of the Si substrate to the shape memory alloy film was studied.It is found that the maximum deflection of the SMA composite diaphragm decreases with the increasing of the thickness ratios.And the mechanical model established in this paper can describe and predict the actuation performances of the SMA composite diaphragm much more accurately when the thickness ratio is larger than five.