压电智能复合材料层合梁的力电耦合 模型及层间应力分析

Under the action of electromechanical loading, it is crucial to predict the interlaminar stress of laminated beams containing uniform graphene sheets-reinforced (GSR) smart piezoelectric composites. If the prediction of interlaminar shear deformation of piezoelectric laminated beams subjected to electromechanical coupling and the material properties vary widely from layer to layer, the interlaminar stress can be very large, which may lead to interlaminar failure. Therefore, an effective electromechanical coupling model is proposed for the interlaminar stress analysis of composite laminated beams with GSR actuators in this paper. First, the proposed model can satisfy the interlaminar continuity condition and only contains four independent unknown variables. By applying Reissner's mixed variational theorem (RMVT), the improved transverse shear stress considering the electromechanical coupling effect is derived. The results obtained from three-dimensional (3D) elasticity theory and the selected model are then used to evaluate the performance of the proposed beam model. The responses of displacement and stress characteristics of composite laminated beams with GSR actuators are systematically studied from the aspects of electromechanical loading, thickness of piezoelectric layer, graphene volume fraction and aspect ratio. It is found that the results acquired from the present model agree well with the solutions of 3D elasticity theory. Moreover, a small volume fraction of graphene can significantly improve the stiffness of laminated beams containing GSR actuators, and further affect the displacement and stress of such structures. Therefore, adjusting the volume fraction of graphene helps to suppress the transverse deflection. Meanwhile, the electrical response of a thick laminated beam containing GSR actuator is more significant than that of a thin one. The thickness of piezoelectric layer has a significant effect on the electric performance of a laminated beam. In addition, the accurate prediction of interlaminar stress of beams can provide reference for the reliability and safety design of intelligent structures, which has great potential in engineering applications.