Vibration Control of A Laminated Composite Plate Subjected to Blast Loading

In this numerical study, vibrations of a cantilevered composite plate subjected to blast loading are suppressed by the use of piezoelectric actuators. Friedlander’s exponential decay function is used for expressing the blast load model. Some parameters of the function are obtained from the experimental studies. A semiloof shell element is developed in order to account for piezoelectric effects. The composite plate is discretized by using the semiloof elements and stiffness and mass matrices of the plate are obtained from the finite element model. In order to reduce the degrees of freedom of the finite element model, mode summation method is used with weighted modal vector including dominant modes in the dynamic behavior. Free vibrations, static behavior and transient vibrations under the blast load are solved by using the full and reduced matrices as well as by using ANSYS software. All results are in a good agreement. State-space equations are obtained from the reduced finite element model. It is proved that the system equations satisfy the controllability condition in order to control the system. Since the system is also desired to be controlled by using a state observer, the observability condition is satisfied for the system. Since the system is on the stability boundary due to neglecting structural damping, the feedback gain matrix of the system is obtained by using optimal linear quadratic regulator (LQR) in order to guarantee the stability of the system. Structural vibrations have been suppressed successfully by using a state observer control system which estimates system states using displacements measured from sensors.