Material design of intelligent plastic products with sound generation function due to snap-through buckling

Audible sound generation due to snap-through buckling during bending deformation was studied using an injection-molded product with a hinge. The sound was clearly generated in a rigid plastic product with a specific shape of the hinge that was markedly deformed. The large elastic energy stored in the hinge by the bending deformation, which was suddenly released during buckling deformation, was responsible for the increased sound pressure. This phenomenon may be exploited as a sensor to control the maximum deformation at bending in intelligent plastic products.