A prediction method for the compressive strength of impact damaged composite laminates

Abstract An analytic method for the prediction of the compressive strength of composite laminates containing impact damage has been developed. Using the characteristics of the impact damage detected by the ultrasonic time-of-flight C-scan technique, the state of the damage is modelled by an elliptical soft inclusion. The degradation of the elastic moduli of the material in the inclusion is determined by a sublaminate buckling analysis. The stress distribution in the laminate containing the inclusion with the reduced moduli is determined using a complex potential method and the stress results are used in conjunction with three failure criteria to predict the residual compressive strength. Compression-after-impact tests on flat laminates manufactured from the Toray T800H/ 3900-2 material have been conducted to produce experimental results for validating the analytical method. Good agreements between predicted residual compressive strengths and experimental results have been obtained.