An enhanced dynamic stiffness modeling method incorporating piezoelectricity for random vibration analysis: application to piezoelectric exciter optimization

Abstract Piezoelectric (PZT) exciters, composed of PZT stack and compliant mechanism, offer significant advantages in mass- and volume-constrained scenarios, such as vibration excitation on dynamic centrifuges. To improve the vibration output performance, dedicated modeling and optimization methods are required. However, the existing modeling methods, such as the dynamic stiffness modeling method, do not couple the structural and PZT effects well, nor do they solve the random vibration problems. In this context, (1) firstly, an enhanced dynamic stiffness modeling method by incorporating PZT effect is proposed to effectively obtain the transfer function from input voltage to output acceleration of PZT exciters; (2) then the dynamic reverse calculation of the expected acceleration power spectrum to the required input voltage power spectrum is derived by the random vibration formula; (3) finally, the optimized design of a PZT exciter is realized by minimizing the total root mean square of the required input voltage. Since this method can calculate the required input voltage quickly and directly from any expected output acceleration power spectrum, it is very suitable for the optimal design of PZT exciters. The results show that the theoretical values of the transfer function obtained in this paper is accurate if the frequency is less than 1000 Hz, while the accuracy is slightly lower if the frequency is more than 1000 Hz. The random vibration output force is raised by 47.1% after the optimization. Additionally, the special relationship between the PZT exciter’s random vibration output force and the load’s mass is revealed, which is different from the characteristics of the electric vibration table.