Dynamic Failure Analysis of Q690D High-strength Steel Welds: A Modified Johnson–Cook Model Validated by Experiments and FEM

This study establishes a modified Johnson–Cook constitutive model and fracture criterion for Q690D high-strength steel butt joints in each microzone (base metal, heat-affected zone, and weld zone) through different states of tensile experiments and split Hopkinson pressure bar dynamic experiments, combined with Abaqus finite element simulation. To verify the accuracy of the model, high-energy dynamic hammer impact experiments are performed on 12 mm-thick butt joint specimens. Results show that the finite element simulation and the experimental failure mode are highly consistent with each other, with an error of only 4.36%, confirming that the model can accurately characterize the mechanical response and failure behavior of Q690D joints under a wide range of strain rates (0.001–5000 s −1 ). This study provides a high-precision simulation method for the impact-resistant design of welded structures. This method exhibits high value for engineering safety assessment.