Published online by Cambridge University Press: 01 February 2011
Thermal expansion is an important actuation mechanism for microelectromechanical system (MEMS). We investigate multi-layered cantilever microactuators actuated by resistive heating with an electric current. The actuator consists of films and sandwiched microheaters. An electrothermal-elastic model for characterizing microactuators is developed. The general analytical expressions relating tip deflection with an applied electric field, temperature change, the film thickness and the applied load at the tip are obtained. The large deflection is considered in the model. The width effect of the cantilever is also investigated using 3D finite element analysis. Based on the analytical solutions and a mixed variable programming (MVP) algorithm, the optimal design of the actuators is presented. The algorithms optimize simultaneously with respect to the number of films and the material choice from a list of candidate materials. The minimum weight and maximum deflection are chosen as the design objectives.