文摘
The fracture toughness of G550 sheet steels to AS1397 has been determined previously for thicknesses of 0.42 and 0.59 mm. All these specimens were found to have stress intensity factors above 100 MN m− 3/2. The fracture toughness of transverse specimens was also found to be below those of longitudinal and diagonal ones for both thicknesses. This paper investigates the fracture behaviour of G450 thicker sheet steels to AS1397 subjected to tension at ambient temperature (approximately 22 °C). In the current testing program, the materials are initially tested under tensile fatigue to create a crack, and then tested under tensile monotonic loading to produce fracture. Elastic-plastic analyses using the ABAQUS program are carried out to validate the FEM model against the test results. Using the FEM model at crack initiation in the elastic range, the fracture toughness under mode I, crack opening, is determined for the three thicknesses of 1.9, 2.4 and 3.0 mm. All tested specimens failed in a ductile manner with no brittle fracture observed.