Damage Evaluation and Residual Strength Prediction of CFRP Laminates by means of Acoustic Emission Techniques

A new approach that integrates acoustic emission (AE) and the mechanical behaviour of composite materials is presented. Usually AE information is used to evaluate qualitatively the damage progression in order to assess the structural integrity of a wide variety of mechanical elements such as pressure vessels. From the other side, the mechanical information, e.g. the stress-strain curve, is used to obtain a quantitative description of the material behaviour. In order to perform a deeper analysis, a function that combine AE and mechanical information is introduced. In particular this function depends on the strain energy and on the AE events energy and it was used to study the behaviour of CFRP composite laminates in different applications: (i) to describe the damage progression in tensile and transversal load testing; (ii) to predict residual tensile strength of transversally loaded laminates (condition that simulates a low velocity impact).