A strain rate-dependent cohesive zone model for shear failure of hat-shaped specimens under impact

The shear behaviors of U71Mn rail steel are investigated during different impact pressures using hat-shaped specimens, where the dynamic shear stress-strain responses of the specimens can be obtained by utilizing a split Hopkinson pressure bar apparatus. The maximum shear tractions are determined through the shear stress-strain curves of the experiments, and cohesive energies are obtained by trial and error method, i.e., the strain waves of the simulations are compared with those of the experiments. It is found that the maximum shear tractions and shear cohesive energies of U71Mn steel are sensitive to strain rates. Further, a strain rate-dependent cohesive zone model is developed to describe the dynamic fracture behaviors. Finally, the crack velocities are acquired under different impact pressures, and the dynamic stress intensity factors and dynamic energy release rates vary with the crack velocity.

Automated summary

The shear behaviors of U71Mn rail steel under different impact pressures were investigated, revealing that the maximum shear tractions and shear cohesive energies are sensitive to strain rates. A strain rate-dependent cohesive zone model was developed to describe the dynamic fracture behaviors. Additionally, crack velocities were measured under different impact pressures, showing variations in dynamic stress intensity factors and dynamic energy release rates with crack velocity.