Numerical Modelling and Simulation of Stiffened Mild Steel Panel Subjected to Near-Field Blast Loading

In the event of localized blast loadings such as the mine blast scenario, the accurate prediction of blast wave propagation and its interaction with structure is complicated even with numerical analysis owing to its high nonlinearity. In the present work, an attempt has been made to investigate the numerical response of mild steel plates with different stiffener cross-sections subjected to near-field blast loading. The numerical model is developed using dynamic nonlinear finite element code for mild steel plate and validated against experimental results. Two approaches are followed for modelling the blast load, a remapping technique using 1D expansion of explosives and the analytical blast boundary conditions available in the Autodyn. The obtained dynamic responses such as pressures, midpoint displacements, and acceleration are matched well with experimental values. The calibrated numerical model is then used for the dynamic analysis of the stiffened mild steel plates subjected to the same explosive phenomena. The effectiveness of the different cross-section stiffeners in mitigating the blast loading was analyzed, and the results were observed and compared with particular emphasis on midpoint displacement–time histories and internal energy absorption of both stiffeners and plates. The effect of thermal softening was also considered using the Johnson–Cook material model, and the results were compared. The performance of stiffened plates against their equivalent thickened plates was analyzed and presented in this work. It is concluded that the U and T-shape stiffeners have better performance in reducing the midpoint displacements.