Comparison of Variational and Generalized Plane Strain approaches for matrix cracking in general symmetric laminates

The current research work is aimed at comparing a stress-based variational approach with generalized plane strain (GPS) model for predicting stress transfer in cracked general symmetric laminates, subject to general in-plane loading. For each model, the fundamental assumptions made on stress and displacement fields, and also procedures for defining boundary conditions and finding solutions are detailed. Moreover, a numerical comparison has been made between the results obtained from two models with regard to stresses, displacements, and thermo-elastic constants of an unbalanced symmetric cracked laminate. Finally, the accuracy and quality of both approaches are examined by checking the satisfaction of known inter-relationships among thermo-elastic constants of cracked laminates. The paper extends an existing variational model so that the effects of residual thermal stresses can be considered. It has been also shown how the displacement field can be determined for a stress-based variational approach.