Performance analysis of thin-layer extensional thermoelectric SMA actuators

We model in this work a thermoelectrically cooled thin SMA layer extensional actuator as a first step towards the design of a high frequency, high force, large strain shape memory alloy (SMA) actuator. The thermoelectric Peltier effect is used to alternately heat/cool the SMA, leading to cyclic phase transformation. The effect of variable actuating load and constant load applied as boundary conditions on the SMA actuator are considered. The frequency response is of interest as also are performance measures like energy conversion efficiency and the energy output per unit volume of active material. based on these measures, the proposed actuator is compared with other various commercially available actuators. The analysis points to the possibility that micron-thick SMA layers, with a low transformation hysteresis and undergoing partial transformation, can deliver frequencies of around 30 Hz at peak stresses of about 145 MPa.