# Dynamic Structural Response of a Corrugated Blast Wall Under Hydrogen Blast Loads
## 5 Discussion and Conclusions  
A comprehensive literature review was conducted on studies that carried out explosion experiments to analyze and compare blast load characteristics of hydrocarbons and hydrogen, and the following results were observed: Hydrogen explosions tended to have greater peak overpressure and shorter duration than hydrocarbon explosions. As the confinement level of explosion spaces increased, the blast load became more severe. An inversely proportional trend between peak overpressure and rising time-to-duration ratio was observed, except for some experiments conducted in spaces with low confinement levels. The aforementioned blast load characteristics are partially consistent with commonly accepted trends in gas explosion characteristics. However, studies that have empirically validated these trends are limited, and those that have directly compared the load characteristics of hydrocarbon and hydrogen explosions are extremely rare. Therefore, the blast load characteristics analyzed in this study might serve as valuable empirical references for the development of safety rules, design standards, and blast load scenarios for hydrogen fuels. If future analyses include a broader range of large-scale explosion experiments and consider the negative phase of blast loads, hydrogen blast load characteristics will be more clearly investigated. Blast load scenarios were selected on the basis of the analyzed blast load characteristics, and the dynamic structural response of a corrugated blast wall was investigated by applying these scenarios to numerical simulations. The blast load scenarios were applied as time-varying pressures over the entire surface of the blast wall. This method offers both practicality and reasonable accuracy when a large number of scenarios need to be analyzed. However, it also involves a certain degree of blast load idealization compared with CFD or FSI simulations. The following results were observed from the numerical simulations: when relatively weak peak overpressures were applied, the blast wall behaved quasi-elastically, and the maximum dynamic structural response was observed around \(t_{\text{d}}/T_{\text{N}}\) of 1 because of the resonance between the blast load and the natural period of the blast wall. However, as the peak overpressure increased and the area of plastic deformation widened, the maximum dynamic structural response was observed in the region of \(t_{\text{d}}/T_{\text{N}}\) higher than 1. Moreover, deflection exceeding the recommended deflection limits and localized fracture were observed in hydrogen blast load scenarios with peak overpressures of 0.5 and 0.7 MPa, respectively. Figure 16: Deformation modes of corrugated blast wall under hydrogen blast loads. The structural responses described in the preceding paragraph demonstrated that the impulse of blast loads and the deformation of blast walls might not be proportional in load scenarios with relatively low peak overpressures, where elastic deformation primarily occurred. Therefore, the P-I diagram, commonly used in the design of blast walls, could be appropriately drawn after some degree of plastic deformation has occurred in the wall. It was observed that the deformation of the blast wall exceeded recommended deflection limits from the blast load scenario with a peak overpressure of 0.5 MPa. This indicates that it is insufficient to block hydrogen blast loads with high peak overpressures, although the existing blast wall is capable of resisting hydrocarbon explosions as intended. Fracture was initiated at the connection between the corrugated panel and the support, as shown by the von Mises stress and plastic strain distributions. This phenomenon highlights that the structural integrity of blast walls depends not only on the panel design but also on the appropriate design of the support and its connection. A new type of diagram for structural response analysis of corrugated blast walls was proposed.