Damage Detection and Identification in Composites by Acoustic Emission, Ultrasonic Inspection and Computer Tomography

Abstract

During the life of carbon fiber reinforced plastic (CFRP) components both production-induced imperfections such as fiber misalignment or pores and usage induced damages such as delamination caused by e.g. low velocity impacts or matrix and fiber failure may occur. Such imperfection and damages may lead to a reduction in the load bearing capabilities where early failure detection could be essential for the prognostic of future behaviour of the structure. Within this paper, the authors present the latest results on on-line Acoustic Emission monitoring of different pre-damaged composite coupons. Therefore, composite panels with different amounts of porosity and different impact damages were produced. The pre-damaged composite samples were subjected to a number of interrupted specific loads – bending, shear, tensile and tensile fatigue loads – to assess the Acoustic Emission signature in dependence of load and damage status. The damage status was further assessed by periodic computer tomography and ultrasonic inspection to compare the different NDT methods.