Dynamic Mechanical Behavior and Optimized Johnson-Cook Modeling of SUS410 Stainless Steel

Accurate constitutive modeling of SUS410 martensitic stainless steel under explosive impact conditions is critical for the safety assessment of protective structures. However, the standard Johnson-Cook (J-C) model, typically calibrated with a quasi-static baseline, often suffers from significant prediction errors when extrapolated to high-strain-rate regimes. This study investigates the dynamic mechanical behavior of SUS410 and proposes an optimized parameter calibration strategy. Quasi-static tensile tests and Split Hopkinson Pressure Bar (SHPB) experiments were conducted to characterize the material’s pronounced strain rate hardening and adiabatic thermal softening effects. Subsequently, two sets of J-C constitutive parameters were calibrated based on distinct reference strain rates: a traditional quasi-static baseline (ε˙₀=0.001s^-1) and a dynamic baseline (ε˙₀=1000s^-1). Numerical verification revealed that the model using the quasi-static baseline resulted in severe non-physical “hardening overflow” at high strain rates (4000 s⁻¹), with the predicted peak stress reaching approximately 2700 MPa, far exceeding the experimental value of ~1000 MPa. Theoretical analysis attributes this discrepancy to the mathematical amplification error introduced by the logarithmic strain rate term Inε˙/ε˙₀ during large-span extrapolation. Conversely, the optimized parameters using the dynamic baseline effectively minimized the logarithmic multiplier effect by anchoring the model to the dynamic regime. This approach successfully decoupled strain rate hardening from adiabatic thermal softening, yielding precise predictions of flow stress across the entire strain rate spectrum. The proposed correction strategy provides a robust physical description for the numerical simulation of SUS410 under extreme impact environments.