Correlation Between Crack Propagation Rate and Cure Process of Epoxy Resins

Abstract

Fracture mechanics approaches are increasingly applied for the characterization of epoxy resins and adhesives mechanical properties. Therefore, the fracture toughness and crack resistance under static load ISO 13586[1] often is regarded as state of the art to figure out material improvements. However, experimental investigations on the fatigue behaviour, thus the crack propagation according to ISO 15850[2], seem to be much more sensitive to characterize the materials for in service loading conditions. At first an efficient testing concept was developed at BAM. Therefore the geometry for a modified single edge notched tensile specimen (SENT) was developed in order to assure an appropriate resolution in measuring the crack length via a CCD-camera [3]. In the next step the influence of the cure temperature on the fracture-mechanical properties was investigated.