Abstract
A three-dimensional (3D) model has been developed for simulation of the physical properties of an electrically driven shape memory alloy (SMA) microactuator used for control of a microvalve. The mechanical behavior is decribed by a two phase macromodel taking into account material and geometrical nonlinearity. The simulation makes use of mechanical, electrical and thermal finite element programs, which are coupled by a program for management of the simulation sequence as well as the exchange of data between the different finite element programs. Mechanical tests confirm the simulated forces and displacements. From the pressure-dependent gas flow in the valve an effective heat transfer coefficient is determined to simulate the convective heat exchange. The simulated heat transfer times are in quantitative agreement with experimentally determined time constants of the microvalve.
