PSI - Issue 77

Christian J. Silva et al. / Procedia Structural Integrity 77 (2026) 631–638 Silva et al./ Structural Integrity Procedia 00 (2026) 000–000

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t = 0.05 s t = 0.10 s

Fig. 6. Comparison of survival space reduction at the final 5 m of the structures (Left: Original design; Right: Modified design)

• Deceleration limits To assess the deceleration levels, the reaction force at the rigid wall was recorded at every instant of the simulation and converted into an equivalent deceleration curve dividing by the mass of the model and applying a moving average over a 30 ms time interval (Figure 8), in line with the requirements of EN 15227. The maximum mean deceleration obtained was 11.3 g for the original design, and 14.7 g for the modified design. In both cases, the results are above the admissible normative value of 10 g.

Fig. 7. Mean deceleration curve for the original and modified designs

3.4. Discussion of the results The comparison between the baseline and modified models highlighted a clear trade-off in crashworthiness performance. While the modified design improved the preservation of survival space, this came at the expense of higher deceleration levels. This outcome reflects the increased stiffness introduced by the modifications, which limited deformation in critical regions but reduced the capacity of the structure to dissipate energy more progressively. From a regulatory perspective, these findings illustrate the complexity of meeting all EN 15227 criteria simultaneously. A design that enhances one safety parameter may negatively influence another, requiring careful