Manufacturing and Testing of Shape Memory Polymer Composite Actuators

Shape memory (SM) polymer composite (PC) actuators have been manufactured by using carbon fibre reinforced (CFR) prepregs and by integrating flexible heaters. The smart device has the structure of a composite sandwich with CFR plies as external skins, an embedded heater and SMP layers in between. Small epoxy foam tablets were also inserted in the laminate centre to increase the maximum attainable deformation during the memory step. These foams were produced by a solid-state process. The sandwich consolidation was obtained in one moulding step. For comparison, a second CFR-SMPC actuator was manufactured without the SMPC foams, thus reducing the final laminate thickness. SM performances of the SMPC devices were evaluated by thermo-mechanical cycling in bending configuration. Memory, constrained-recovery and free-recovery tests were carried out. Shape fixity and shape recovery were extracted as well as recovery loads. Results show the optimal SM behaviour of the new sandwich architecture.