Finite element modeling of composite plates with total imperfect interface subjected to impact loading

This project report is devoted to the modeling of the impact behavior of laminated composite plates, with a special emphasis on incorporating interfacial imperfection. In most analytical and numerical works on composite materials, a perfect interface between adjacent laminae is assumed which implies continuous displacements and tractions across laminate. In many cases of practical interest, however, the assumption of a perfect interface is inadequate. This project report aims at the finite element formulation for the effects of different imperfect bonding intensities on the response of a laminated plate subjected to a transverse low velocity impact using MATLAB. In this study, the imperfect bonding is incorporated into the formulation by introducing an imperfection factor, R, to the interface stiffness modeled using a well-defined virtually zero-thickness interface element. The kinemati cally consistent mass formulation is used to formulate the mass matrix and the impact force is evaluated using a simple linear model. New mark beta method, an implicit method of direct integration, is used in the present study for the solution of the linear transient response of the plate. From analysis, it is found that the fundamental non dimesional frequency, absorbed energy and the central deflection increase with an increase in imperfection factor. Besides, the orientation of laminae is also observed to affect the impact behavior of the laminated composite plate