Simulation research for fluid-solid interaction performance of a piezoelectric bimorph actuator applied in servo valves

In order to describe the effect of viscous fluid on the piezoelectric bimorph actuator used as pilot stage driver of a two-nozzle flapper servo valve, two simulation methods were utilized in this paper. Firstly, based on the principle of piezoelectric bending deformation and the Euler-Bernoulli beam equation, the dynamic model of the piezoelectric bimorph actuator (PBA) is built in the MATLAB/Simulink platform and the effect of hydraulic oil on the piezoelectric bimorph actuator is empirically taken into account by means of additional mass and damping. Furthermore, the piezoelectric effect and fluid-solid coupling module in COMSOL are used to present the effect of fluid on piezoelectric bimorph actuators. These models results indicated that the amplitude of the piezoelectric bimorph actuator strongly relies upon the working frequency and the effect of viscous fluid on the actuator. This work serves as a guidance for the design of piezoelectric bimorph actuators for a double nozzle flapper servo valve.