A PREDICTION METHOD FOR THE COMPRESSIVE STRENGTH OF IMPACT DAMAGED COMPOSITE LAMINATES

An analytic method for the prediction of the compressive strength of c omposite laminates containing impact damage has been developed. Using the characteristics of the impact damage detected by the ultrasonic ti me-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 incl usion with the reduced moduli is determined using a complex potential method and the stress results are used in conjunction with three failu re 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 f or validating the analytical method. Good agreements between predicted residual compressive strengths and experimental results have been obt ained.