Design of a polymeric prototype with variable geometry controlled by shape-memory strips

Shape memory alloys are successfully used in several mechanical devices, replacing expensive and cumbersome mechanical systems. In this communication a preliminary study for the design of an actively deformable structure is presented. The possibility of increasing the performance of cooling fans in earth-moving engines by controlling the geometry of the fans’ blades is examined. A prototype made of a NiTi shape memory strip fixed to the surface of a polymeric plate is briefly illustrated. The heat treatment parameters necessary to memorise the desired shape of the strip are determined experimentally, and a theoretical model is developed to reproduce and optimise the behaviour of the prototype.