Multiobjective design optimization procedure for control of structures using piezoelectric materials

Piezoelectric materials can be used as sensors and actuators for structures that require active vibration control and lack sufficient stiffness or passive damping. Efficient implementation of these actuators requires that their optimal locations on the structure be determined and that the structure be designed to best utilize the properties of the actuators. A formal optimization procedure has been developed to address both of these issues. A gradient based multiobjective optimization technique is used to minimize multiple and conflicting design objectives associated with both the structure and the control system design which is also coupled with the actuator location problem. Objective functions such as the fundamental natural frequency of the structure and energy dissipated by the piezoelectric actuators are included in this study. Constraints are placed on the mass of the structure, displacements and applied voltage to the piezoelectric actuators. Design variables include parameters defining both the control system and the structure. The finite element method is used to model active damping elements which are piezoelectric actuators bonded to a box beam. The optimization procedure is implemented on a flexible 2-D frame.