Piezoelectric Control of Edge Debonding in Beams Strengthened with Composite Materials: Part II - Failure Criteria and Optimization

Abstract

The prevention of the edge debonding failure in RC beams strengthened with externally bonded composite materials by means of optimized piezoelectric control is investigated. The study uses the mathematical model derived and verified in Part I of this paper to assess the structural response of the strengthened beam to the electrical and mechanical loads. The electrical actuation is optimized using two objective functions corresponding to two approaches for the prediction of the debonding failure. The first approach is based on evaluation of the stresses at the critical region near the edge of the bonded strip. The second approach adopts the fracture mechanics concept of the energy release rate, which is evaluated through the generalized J-integral. The formulation of the objective functions and the constraints associated with the restricted operational range of the piezoelectric actuators is presented. A procedure for the construction of the linear or quadratic response and objective functions through a relatively small number of evaluations of the structural model is presented and discussed. A numerical optimization study that focuses on the ability of different combinations of piezoelectric actuators to control, prevent, or delay the edge debonding failure is presented. The main contribution of this study is in providing a systematic approach to optimize the piezoelectric control under different debonding failure criteria and in demonstrating the feasibility of using the piezoelectric system in the full-scale civil engineering structure.