Deflection control of elastically restrained laminated frames under deterministic and uncertain loads using induced strain actuators

Optimal induced strain actuator sizes for an L-shaped laminated frame are determined under deterministic and uncertain loads with the objective of minimizing the tip deflection. The bending moments generated by the induced strain actuators control the deflection in order to minimize the maximum deflection. The frame is elastically restrained at the tip point and is subjected to a tip load which is specified for the deterministic case and lies in an uncertainty domain in the uncertain case. The specific uncertain loading studied in the present paper involves a load of given magnitude but of unknown direction which should be determined to induce the highest tip deflection caused by the least favorable loading. The effects of the elastic restraints and actuator locations on the deflection behaviour are investigated. It is shown that the optimal actuator size depends on the magnitude of the moments provided by the actuators. Moreover, it is observed that a deterministic design under an uncertain load leads to excessive deflections indicating the necessity of a robust design. (c) 2006 Published by Elsevier Ltd.