Corotational nonlinear dynamic analysis of laminated composite shells

The formulation and application of an implicit time-stepping scheme based on the corotational formulation for nonlinear dynamic analysis of laminated composite shells is the main objective of this work. The time-integration algorithm used here is a particular form of a mid-point procedure which approximately conserves the energy of the system allowing the computation of long-term response in problems presenting large translations and rotations. This algorithm has been applied to problems involving frame structures, but few works dealt with shell analysis and practically no studies were developed with laminated composite structures. The corotational procedure is independent with respect to the core linear element formulation and operates as transformation of quantities between element local and global reference systems. In this work shells are modeled by a flat triangular finite element obtained by a novel combination of a high performance membrane element and a simple and efficient plate element developed for laminated composite analysis considering first order shear flexibility. Examples are presented to demonstrate that the corotational time-stepping scheme is able to solve complex nonlinear dynamic problems with large body motion. Laminated composite shell stiffness is shown to be correctly determined by the core element formulation. Results indicate that, in spite of its simplicity, the present algorithm can efficiently solve hard nonlinear dynamic problems involving laminated composite shell.