Finite Element-Based Numerical Investigations of a Beamlike Actuator Combining Shape Memory and Superelastic Effects

It has been amply demonstrated that the development of SMA actuators has a great potential of application in several branches of industry. Obviously, the efficiency of the actuators depends both on the inherent features of the materials they are made of and the geometric characteristics of the devices. This work considers a particular type of actuator first conceived by [1], consisting in the association of two cantilever beams, the first presenting the shape memory effect and the second presenting the superelastic effect, coupled mechanically so as to guarantee two equilibrium positions and thus a stand-alone cyclic actuator, in which the superelastic beam provides the bias action. Numerical simulations of the behavior of the actuator are performed using the commercial finite element software COMSOL, which implements the Boyd-Lagoudas thermomechanical model. The goal of the simulations is to characterize the actuation range of the actuator, in terms of maximum displacement obtained at the tip. The effect of the dimensions of the beams on the tip displacement under some load scenarios is investigated. The results provide guidelines for the design of the actuator to fulfill specific requirements, also suggesting the use of numerical optimization for the optimal design of the actuator accounting for constraints.