Determination of normal force for optimal energy dissipation of harmonic disturbance in a semi-active device

A semi-active device is presented for vibration control using energy dissipation by dry friction at contact surfaces. The device uses two piezoelectric stack actuators to apply a normal force between a moving mass component and two friction pads. The objective is to adjust the normal force in order to reach the maximal power dissipated. The theoretical optimal normal force is predicted with an analytical model of the device. The normal force generator is modelled using the piezoelectric constitutive equations. The LuGre model is proposed for the dry friction modelling and then reduced to the Coulomb model. The parameters of the spring-mass-damper, force generator and dry friction models were identified experimentally. The dissipated power is obtained from the experimental measurements and presented with respect to the operating parameters (voltage, frequency, excitation force) and the results validate the presented optimal constant normal force to maximize the energy dissipated.