Standardizing the Single-Fibre Pull-Out Test for Fibre-Matrix Adhesion Characterization: Method and Insights

The standardization of the micromechanical single-fibre pull-out test is urgently requested by the industry. The corresponding DIN SPEC 19289 "Fibre-reinforced Composites - Measurement of Interfacial Shear Strength by means of a Micromechanical Single-Fibre Pull-Out Test" was recently published within the scope of the publicly funded WIPANO project "WiPull", which was conducted between the partners Fraunhofer IGCV, Faserinstitut Bremen and Textechno H. Stein GmbH & Co. KG. This project also included testing of the most relevant thermoplastic matrices like PA6, PP, PEEK and PC in combination with carbon fibres, recycled carbon fibres, glass, and natural fibres. This paper includes key findings of the WiPull project including the impact of tempering, ageing, degradation, and temperature profiles on the measured fibre-matrix adhesion strength. Furthermore, results of the round robin trials are shown and discussed.