Mode-I Fracture Investigations of Pressure Vessel Steels: Experimental and Simulation Study

The current paper reports the development of experimental-simulation coupled approach to investigate fracture behavior of SA 387 and SA 516 pressure vessel steels. Mechanical and fracture properties are derived from tensile and fracture tests, respectively. Cohesive model is implemented for fracture studies of pressure vessel steels within XFEM framework. To simulate crack, gradual degradation of the elements is considered and suitable criterion is proposed to select cohesive parameters (i.e., cohesive energy, cohesive stiffness and cohesive strength). Simulations are performed to study effect of traction separation laws (exponential, partly constant and constant). The simulation results are validated with experimental data. Among the chosen traction separation laws, partly constant and constant traction separation laws are found suitable for SA 387 and SA 516 pressure vessel steel, respectively. It has also been confirmed from the fracture surface morphology study that SA 387 steel has less fracture resistance compared to SA 516 steel.