Actuation of elastomeric rods with embedded two-way shape memory alloy actuators

The modelling and experimental results of deformations of elastomeric rods with embedded two-way shape memory effect actuators is presented in this work. A procedure is established to train Nitinol shape memory alloy (SMA) wires to exhibit the two-way shape memory effect, a hysteretic behaviour involving a therrmally induced, zero-stress, kinematically reversible transformation strain. A flexible silicone elastomer rod is embedded with two of these SMA actuators at an offset from the neutral axis. Resistive heating of an SMA actuator causes SMA transformation strain recovery and hence induces bending strain in the rod; cooling of the SMA actuator back to room temperature relaxes the rod to its initial position. The inclusion of two opposing actuators provides the ability to actuate the rod in two opposing directions. The deflection of a flexible rod with embedded two-way SMA actuators is modelled with both a general theory of flexible rods and an approximate formula. The experiments and modelling demonstrate the feasibility of using SMA actuators for large shape change in active flexible structures.

Actuation of elastomeric rods with embedded two-way shape memory alloy actuators Academic Article