Development of interphase engineering techniques for the ductility improvement in CF/EP composites – Comparison of NDT methods for delamination localization

Abstract In our ongoing research we are developing interphase engineering methods to improve ductility in endless fiber reinforced composites. In the present paper we locally weakened interfacial adhesion between the fibers and the polymer matrix by the application of a designed interlaminar pattern created by 3D printing from PCL (polycaprolactone), which can be solved in the epoxy resin matrix, leaving a low adhesion pattern, but not creating a third phase in the composite. We produced composites with three different weakened adhesion zones and investigated the compressive properties and the capability of acoustic emission (AE), full field digital image correlation (DIC) and infrared thermography (IR) to localize these zones.