Damage evolution in bimodular laminated composites under cyclic loading

This work deals with layered composite structures under cyclic loading. In particular, bimodular material laminates are considered and the Bert model is adopted. The analysis is developed using a finite element procedure based on a theory which takes into account the shear deformability (layer-wise deformation plate theory). The adoption of this theory is important to improve the stress evaluation by obtaining a better utilisation of the polynomial failure criteria for the identification of the cracked zones. To determine the stiffness reduction due to the damage evolution, the Laws et al. formulas are adopted for two types of crack (penny-shaped and slit-aligned). The analysis of the structures under cyclic loading is carried out by adopting some reasonable hypotheses on the reduction of the mechanical parameters and on the crack detection. (C) 2001 Elsevier Science Ltd. All rights reserved.