A Case Study of Combined Application of Smart Materials in a ‎Thermal Energy Harvester with Vibrating Action

This paper demonstrates a case study of a combined application of smart materials in a thermal energy harvester with vibrating action. The conceptual design of the harvester is based on a Shape Memory Alloy wire attached to the free end of a piezoelectric flexible cantilever beam intended for generation of electrical energy utilizing a constant heat source. A mathematical model containing three differential equations describing the dynamics of the mechanical, electrical and thermal subsystems is developed. The Shape Memory Alloy hysteretic behaviour is considered in the mathematical model. An essential observation is the system oscillates at two frequencies lower one of which depends on the temperature time constant and the higher one is determined by the natural frequency of the mechanical subsystem. The comparison of the numerical solutions and the experimentally obtained graphs of the harvester output characteristics shows a good degree of coincidence.