Shape memory alloy-piezoelectric active structures for reversible actuation of bistable composites

A study was conducted to introduce an actuation mechanism, called shape memory alloy-piezoelectric active structures (SMAPAS) that combined the advantages of the piezoelectric shape memory alloy (SMA) materials to achieve self-resetting bistable composites. The approach used piezoelectric actuation to provide a rapid snap-through with significant degree of control and a relatively slow, but high-strain SMA actuation to reverse the state change. A thin cantilever beam of carbon-fiber or epoxy material was used to demonstrate the two-way actuation. The composite lay-up procedure was a standard method for the manufacturing of carbon laminates through a standard cure cycle to a maximum cure temperature of 125°C and a pressure of 85 psi. A macrofiber composite piezoelectric actuator was used to conduct the investigations and it consisted of aligned piezoelectric fibers with an interdigitated electrode to direct the applied electric field along the fiber length.