Evolution of a fracture mechanism in a polymeric composite subjected to fatigue with the self-heating effect

In this paper, the authors focused on evaluation of fatigue fracture mechanisms accompanying fatigue of polymeric composites with an occurrence of a self-heating effect. In order to reflect degradation processes and their evolution at various values of a self-heating temperature with a possibility of analyzing an internal structure of cracks and delaminations occurring during fatigue, X-ray computed tomography tests were performed. Specimens made of a GFRP composite were subjected to cyclic loading in order to stimulate a non-stationary self-heating of the structure. The performed tests allow for characterization of morphology of damage occurring during fatigue loading of polymeric composites subjected to dominated self-heating, and, based on the performed observations, determination of a critical self-heating temperature value, which causes appearance of internal fracture in a structure. Moreover, a continuous acquisition of a self-heating temperature and acoustic emission during fatigue allows for connection of fracture events with particular events observed in temperature evolution and acoustic emission signals, which, in turn, allows for better understanding of formation of fracture in a structure in such loading conditions.