Experiments on the mode II fracture toughness in ENF tests of CFRP curved beams

Abstract

The purpose of this study is to establish end-notched flexure (ENF) tests of curved beam specimens cut from tanks or cylinders. To provide data reduction methods for experiments, a compliance-based beam method (CBBM) for curved beams in ENF tests is proposed based on the previously established Euler–Bernoulli curved beam theory formulations of ENF tests. ENF tests were conducted using curved beam specimens with three different curvature radii, and the results were in good agreement with the curved beam theory. In addition, the fracture toughness values obtained from the proposed CBBM for curved beams were validated using three-dimensional finite element (FE) analysis. The results revealed that the FE analysis with the measured fracture toughness agreed well with the experimental load–displacement curves, verifying the validity of the obtained fracture toughness values for curved beams.