Modeling of an integrated shape memory alloy micro-actuator under bending sollicitation

Abstract

In this paper, we give a model of shape memory alloys (SMA) thin blade working in bending. This work is based on the general study and the modeling of an integrated shape memory alloy micro-actuator controlled by thermoelectric effect called the « Ω module ». This micro-actuator is composed of a NiTi thin blade on which are placed two Bismuth Telluride ingots used to control the temperature of the SMA blade, by thermoelectric effect. The model of the bending behaviour is based on a general macroscopic description of the thermomechanical behaviour of shape memory alloys. The self-accommodating (pure thermal effect) and oriented (stress-induced) martensites are taken into account. The numerical resolution by finite differences leads to the comprehension of phase transformation for pseudo-elastic and thermal cycling bending tests