An engineering approach for predicting residual strength of carbon/epoxy laminates after impact and hygrothermal cycling

A semi-empirical analysis on residual compressive strength (RCS) of carbon/ epoxy woven composite laminate was developed which included the damage effe cts caused by impact and hygrothermal cycling. Impact damage is modelled as a soft inclusion with an exponentially reduced stiffness and the stiffness is further reduced due to hygrothermal cycling. A complex variable method was used to determine the in-plane stress distribution near the impact-indu ced damage and point stress failure criterion is then used to predict the f ailure load. Based on the semi-empirical model, the RCS can be related to d amage width, damage intensity, undamaged strength and a degradation factor due to hygrothermal cycling, The results from the analysis coincide reasona bly well with the experimental data for the plain-woven fabric laminates. ( C) 2000 Elsevier Science Ltd. All rights reserved.