Stress recovery in laminated composite and sandwich panels undergoing finite rotation

Laminated composite and sandwich panels are susceptible to mechanical damages in the transverse direction due to their relatively low strength in the transverse direction. For such damages to occur, laminated composite and sandwich panels usually experience geometrically nonlinear deformations. Therefore, analysis taking large deformations into account is required for predicting mechanical damages such as delamination. In the present study, a nonlinear predictor-corrector procedure is adopted for the accurate recovery of stresses in laminated composite and sandwich panels undergoing geometrically nonlinear deformations. It is a post-processing procedure based on the three-dimensional stress equilibrium equations, combined with an 18 node assumed strain solid finite element model based on the Hellinger-Reissner principle tailored for large rotation analysis of laminated composite and sandwich panels. The effectiveness of the proposed approach is demonstrated by means of numerical examples of laminated composite and sandwich panels subjected to mechanical loading and uniform temperature gradient in the thickness direction. (C) 2002 Published by Elsevier Science Ltd.