Optimization of actuator placement in a truss-cored sandwich plate with independent modal space control

The determination of optimal locations of actuators is an important issue in the field of vibration control in structures. In this paper, a practical method for the optimal actuator placement in a truss-cored sandwich plate based on independent modal space control (IMSC) is proposed. It is shown that the modal strain energy (MSE) alone is not enough to determine the actuator locations since the system may become uncontrollable, especially when the structure is symmetrical. Moreover, it is found that the controllability can be measured through the singular values of the input matrix. Therefore the singular values of the input matrix together with the modal strain energy may serve as an effective optimization index for actuator placement. Numerical examples are presented to show that the maximal actuator force can be significantly reduced after the optimization in order to achieve an equal modal control force.