# Dynamic Structural Response of a Corrugated Blast Wall Under Hydrogen Blast Loads
## 4 Results  
Figure 10 shows the maximum and permanent displacements at the mid-span for all blast load scenarios. The x-axis presents durations nondimensionalized by the natural period (\(T_{\text{N}}\)) for each scenario. As the peak overpressure increased, the maximum displacement also increased, but the increasing trends over duration depended on the  
\begin{table}
\begin{tabular}{c c c} \hline  & **Hydrocarbon** & **Hydrogen** \\ \hline Peak overpressure & 0.05/0.1/0.2/0.3 MPa & 0.05/0.1/0.2/0.3/0.4/0.5/0.6/0.7/ \\ (\(p_{\text{peak}}\)) & & 0.8/0.9/1.0/1.1/1.2 MPa \\ Duration & 0.01/0.02/0.03/0. level of peak overpressure. For load scenarios with peak overpressures of 0.1 MPa or less, because elastic deformation occurred at the corrugated panel and supports, the resonance between blast load and structure acted as a significant factor in determining structural response. Therefore, the greatest deformation was observed around a \(t_{\text{d}}/T_{\text{N}}\) of 1. In blast load scenarios with peak overpressures of 0.2-0.3 MPa, plastic deformation at the supports spread to the corrugated panel, and the stiffness of the blast wall therefore decreased. This decrease in stiffness elongated the natural period of the blast wall [67; 68], and, thus, the greatest structural deformation was observed after \(t_{\text{d}}/T_{\text{N}}\) of 1. When peak overpressures are 0.4 MPa or greater, all load scenarios correspond to only hydrogen explosions. In these scenarios, when the peak overpressure increased by 0.1 MPa, the maximum and permanent displacements increased more rapidly than in the hydrocarbon load scenarios. This indicated that plastic deformation occurred throughout the blast wall and rapidly increased. In the case of corrugated blast walls with angle-type supports, plastic deformation generally occurs first in the supports and then in the panel. This sequential relationship could be confirmed by the permanent displacement and residual strain energy diagrams. In load scenarios with a peak overpressure of 0.2 MPa, the strain energies at the corrugated panel were so insignificant and did not remain permanently. However, permanent displacements at the mid-span began to be observed because plastic deformation occurred at the supports. Figure 11 presents the maximum and residual strain energies of the corrugated panel for all blast load scenarios. Increasing trends in both the maximum and residual strain energies were observed with higher peak overpressures. This trend indicates that larger deformations occurred in the panel as the peak overpressure increased. From blast load scenarios with a peak overpressure of 0.3 MPa, the maximum strain energy increased significantly, and the residual strain energy began to appear. The presence of residual strain energy demonstrates that plastic deformation occurred in the corrugated panel. Residual strain energies became more pronounced in blast load scenarios with peak overpressures of 0.4 MPa or greater. This suggests that the panel is likely to absorb a greater portion of blast loads under such loading conditions. Figure 10: Dynamic structural responses depending on nondimensionalized time and peak overpressure: (**a**) maximum and (**b**) permanent displacements at the mid-span. In blast load scenarios with peak overpressures of 0.6 MPa or greater, plastic deformation at the corrugated panel rapidly increased, causing large deformations of the entire blast wall. No resonances between the blast load and natural period were observed because of the significant decrease in structural stiffness caused by large deformations. A localized or global fracture was observed in certain load scenarios with peak overpressures of 0.7 MPa or greater. As blast walls with even the slightest fracture could be considered to be in a failure state, these cases are not plotted in Figures 10 and 11, corresponding to the part beyond the cut curves in these figures. As the peak overpressure increased, the duration necessary to cause a fracture shortened increasingly.