ON THE FIXED POINT OF FREQUENCY RESPONSE OF SINGLE DEGREE-OF-FREEDOM BASE EXCITED ISOLATION WITH PIEZOELECTRIC ENERGY HARVESTING

Abstract

Vibration isolation is a fundamental device to protect machines or vehicles from unwanted vibration. Adding the energy harvesting capability to the vibration isolation can extract the waste heat energy.  This paper considers the single-degree-of-freedom (SDOF) base excited isolation with piezoelectric energy harvesting. The purpose of this paper is to find how the energy harvesting circuit affects the fixed point of the frequency response. The fixed point is an important point in design the vibration isolation. The analytical frequency response method is used. The motion equation is written in the dimensionless form. The frequency response analysis of the system reveals the fixed point in the frequency response plot. The position of the fixed point does not depend on the circuit resistance. Two parameters of the piezoelectric harvesting circuit including the dimensionless resistance and the dimensionless force factor can be changed in isolation design. The design strategy is to make the fixed point and the peak point coinciding. Based on the strategy, the optimal condition of the isolation is expressed by a relation between the dimensionless resistance and the dimensionless force factor.