Experimental and numerical investigation on crack propagation in high strength steels and conventional steels

The application of high strength low alloy steels like S690, S700, S960 increased over the years when compared to the conventional structural steels in the field of construction and heavy industrial equipment to optimize the weight with a focus on sustainability. This paper presents the experimental and numerical results on fracture mechanics-based crack propagation comparing the high strength steel and the conventional steels. The methodology followed for test procedure is based on the ASTM E647 standard and a compact tension (CT) test sample design. The experimental results are used to validate finite element analysis (FEA) for crack propagation based on the ANSYS SMART (separating, morphing and adaptive remeshing tool) technology. Fracture mechanics-based fatigue crack growth rates are compared with the different grades of steel at the same stress ratio. The experimentally determined Paris Law coefficients m & C for the different steels are updated on the FEA model as to validate the results. Experimental crack mouth opening displacement (CMOD), and back face strain (BFS) results are post processed to obtain crack length versus cycles.