In situ computed tomography for the characterization of the fatigue damage development in glass fiber-reinforced polyurethane

Abstract

Abstract Fiber-reinforced polymers show a continuous material degradation under cyclic loading, which is why damage development has to be investigated for an exact assessment of fatigue properties. In order to obtain information on damage in the internal volume, conventional mechanical test methods require accompanying support by further developed techniques. In this study, a methodology for in situ computed tomography has been developed and applied to glass fiber-reinforced polyurethane. Polyurethane has advantages over epoxy in terms of impact strength, damage tolerance and abrasion, which are important for various applications. Fatigue properties, on the other hand, are largely unknown. Optimized imaging parameters for computed tomography have been established in order to obtain detailed 3D volume images suitable for analysis. The 3D volumes of the damage state were recorded according to defined fatigue load steps and used to evaluate and correlate the damage development with the mechanical properties. The results confirm known damage characteristics of fiber-reinforced composites but also show material and structure-related differences in crack formation and propagation.