THE RESEARCH ON DAMAGE DETECTION OF CURVED BEAM BASED ON PIEZOELECTRIC VIBRATION ENERGY HARVESTER

This paper established dynamic model of forced vibration of the curved piezoelectric energy harvesters with cracks. The Green’s function of piezoelectric curved beam with cracks is obtained based on analytical solutions of vibration equation of the electromechanical coupled Prescott models and continuity conditions at crack sections. The system equation of the electromechanical coupled model with cracks is decoupled and the output voltage of the forced vibration of the damaged curved piezoelectric energy harvester under forced vibration is acquired by the linear superposition principle. The damaged conditions of the piezoelectric curved beam can be detected by inverse method, which is proposed in this paper and suitable for the structure in vibration．In the numerical simulations, the analytical solutions of damaged piezoelectric curved beam that have zero crack depth are compared with results in the previous references. The validity of solutions in this paper is verified. The influence of the crack depth, crack location, material geometric parameters and damping on frequency responses of the voltage is investigated separately. The results show that the effect of cracks on the curved piezoelectric energy harvester is more complicated than that of the straight beam model. The voltage response of damaged piezoelectric curved beam is proportionally decrease at the first order frequency that is the first order frequency of heathy curved beam. And the damaged piezoelectric curved beam is excited out the second-order frequency, which is the first order frequency value of healthy piezoelectric curved beam in an short-circuit. The depth of cracks and the range of cracked positions in the piezoelectric curved beam can be determined by monitoring the change of voltage response, which verifies the feasibility of the inverse method. It is feasible and accurate to use the solution of vibration problem to detect the health condition of damaged piezoelectric curved beams.