Fracture study in notched graphite specimens subjected to mixed mode I/II loading: Application of XFEM based on the cohesive zone model

摘要

The aim of the present research is to predict the fracture load of key-hole and U-notched graphite components under mixed mode I/II loading by means of the extended finite element method (XFEM) based on the linear cohesive zone model (CZM). For this purpose, two series of fracture experiment conducted on several key-hole notched rectangular graphite plates, and also U-notched Brazilian disk graphite specimens and reported previously in the literature are presented. Then, the experimentally obtained fracture loads of the tested graphite specimens for both fracture test series are theoretically estimated by means of XFEM in combination with CZM. Since the graphite specimens have perfectly brittle behavior, the linear elastic notch fracture mechanics (LENFM) assumption is utilized. For different notch geometries, the experimental and theoretical results are plotted in the form of the variations of the fracture load versus the notch tip radius. Finally, it is shown that XFEM-CZM approach could successfully predict the experimentally obtained fracture loads of the tested specimens.