Dynamic evaluation of smart piezoelectric composite materials actuators

This thesis presents the studies conducted on a Lightweight Piezo-composite Curved Actuator, LIPCA. The project aimed to identify important actuator's design paramenters and their influence on the actuation's displacement as well as on the resonance frequency.Three different types of LIPCAs were manufatured and tested. The actuators were tested under cantilever boundary conditions and were actuated under different frequencies and voltage ranges. The resonance frequency decreases as the input electric field increases due to the material softening of the piezoceramic. FEM simulation were performed in order to reproduce the testing's results. Some parameters were found to influence the final performance and also to be influenced by the electric input voltage and by the stress state into the piezoceramic layer. Finite element simulation was used to estimate the reduction of the piezoelectric's elastic modulus and the relation of the piezoelectric strain coefficient with the electric input voltage. The reduction in modulus and the changing of the piezoelectric strain coefficient change differently in each LIPCAs. These parameters are strongly influenced by the stress state inside the piezoceramic layer.