# Experimental and Numerical Evaluation of Calcium-Silicate-Based Mineral Foam for Blast Mitigation
## 5 Conclusions  
This study presents an experimental and numerical investigation of the near-field blast protection of aluminum plates by using AAC-based mineral foam as a crushable core in sacrificial cladding. Blast tests are conducted using 20 g of C4 (25 g TNT equivalent) explosive, both with and without the sacrificial cladding, positioned 250 mm from the backplate's center. Maintaining a constant distance between the explosive and the structure increases the blast load applied to the front skin. Six configurations of 60 mm thick foam are considered. Moreover, the influence of the foam configurations and the charge mass on the effectiveness of the sacrificial cladding is explored by performing numerical simulations. The findings reveal the following:  
1. The numerical model accurately reproduces the deflection profile at mid-span with a relative error of about 5%. Notably, the SPH approach proves to be robust in predicting the experimental results. 2. The sacrificial cladding exhibits a favorable protective effect on the aluminum plate, reducing the maximum deflection and mean permanent deformation at the center of the plate by at least 30% in configuration F and up to 70% in configuration C.
3. The foam configuration significantly influences the energy dissipation of the sacrificial cladding. Specifically, increasing the \(\zeta\) value, denoting the ratio of the foam's lateral surface to its total volume, results in an enhanced protective effect of the cladding. However, when \(\zeta\) exceeds an optimal value, the performance of the SC is decreased. This optimal \(\zeta\) value minimizes the maximum deflection and permanent deformation while maximizing the absorbed energy by the foam. The SC's decrease in effectiveness is primarily due to excessive front skin deformation leading to non-uniform foam crushing. 4. Non-deformable front skin has been adopted to address the influence of front skin deformability. This latter demonstrates an increased effectiveness of the SC, particularly for \(\zeta\) values above the optimal value obtained when using a deformable front skin. Notably, non-deformable front skin increases maximum deflection reduction and foam energy absorption by up to approximately 30%. 5. Positive protection effects are observed for all loading conditions examined. In summary, this study demonstrates the effectiveness of using calcium-silicate mineral foam-based sacrificial cladding for near-field blast protection of aluminum plates. The experimental and numerical findings shed light on the influence of foam configuration  
Figure 29: Influence of front skin deformability on the absorbed energy by the foam for different foam configurations. and charge mass on the protective performance of the sacrificial cladding. These insights contribute to advancing the understanding of blast mitigation techniques and have practical implications for designing and implementing protective measures in relevant applications. Specifically, this solution is expected to be a cost-effective and lightweight protection concept for standard ISO container shelters in international operations. Conceptualization, D.L. ; methodology, A.A., M.B.R., B.B. and H.O. ; software, A.A. and B.B. ; validation, A.A. and H.O. ; investigation, A.A., M.B.R. and B.B. ; resources, D.L. ; data curation, A.A., M.B.R. and B.B. ; writing--original draft preparation, A.A.; writing--review and editing, A.A., D.L. and L.P.; visualization, A.A.; supervision, D.L. and L.P.; project administration, D.L. and L.P.; funding acquisition, D.L. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author. The authors are grateful to the staff of the Laboratory of Structures and Effects of Explosion Department of the Royal Military Academy in Brussels for their support and assistance in performing the different steps of the experimental work.