Nonlinear analysis of rectangular laminated plates

Dynamic Relaxation method coupled with finite differences is used for the analysis of rectangular laminates. In this method, the equilibrium equations are converted to dynamic equations by adding damping and inertia terms. These are then expressed in finite differences form and the solution is obtained by an iterative procedure.The functions of the DR program are as follows: read the data file, compute the stiffness of the laminate, the fictitious densities, the velocities and displacements and the mid-plane deflections and stresses, check the stability of the numerical computations, convergence of the solution, and the wrong convergence, compute through thickness stresses in direction of plate axes, and transform through thickness stresses in the lamina principal axes. The errors inherent in the DR technique include discretization error which is due to the replacement of a continuous function with a discrete function, and an additional error due to the non-exact solution of the discrete equations. The present DR results are compared with similar studies to validate the DR program, and the results are found of acceptable accuracy.