PSI - Issue 81

Anandito Adam Pratama et al. / Procedia Structural Integrity 81 (2026) 58–65

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Fig. 5. Obtained finite element results: (a) maximum deflection, and (b) total impulse.

To further quantify the sensitivity of the structural response under constant SF, relative differences in maximum deflection and total impulse among the core variations are summarized in Table 3. For maximum deflection, the variations remain within a low to-moderate range, with changes generally below 11% for the S-, X-, and U-cores, while the Y-core shows higher sensitivity. In contrast, total impulse exhibits greater sensitivity, with the largest relative increases observed for the U-core (29.4%) and Y-core (26.8%). This indicates that the impulse response is more sensitive to variations in explosive parameters than deflection, particularly at the initial comparison stage. Although the overall differences between core configurations remain below 30%, the results clearly demonstrate that maintaining a constant SF does not lead to identical structural responses. Variations in explosive mass and stand-off distance still produce noticeable differences in both deformation and impulse transfer, highlighting the limitations of SF as a standalone indicator of UNDEX severity. The deformation patterns for each core configuration are illustrated in Fig. 6 for SF variation 3 (TNT mass of 4 kg and stand-off distance of 2 m). The S-core exhibits pronounced localized deformation, indicating limited load redistribution capability. In contrast, the X-core and U-core display more uniform deformation patterns, reflecting improved load transfer and higher structural robustness. These observations are consistent with the quantitative results and underline the engineering advantage of cellular core designs, particularly X-core and U-core configurations, for enhancing blast resistance in underwater explosion scenarios.

Table 3. Sensitivity analysis based on the percentage of maximum deflection and total impulse. Core type Ratio

Maximum deflection

Total impulse

7.4%

13.8% 20.7%

S1 → S2 S1 → S3 S2 → S3 U1 → U2 U1 → U3 U2 → U3 X1 → X2 X1 → X3 X2 → X3 Y1 → Y2 Y1 → Y3 Y2 → Y3

10.8%

S

3.1% 4.3% 7.2% 2.9% 5.6% 8.6% 2.9%

6.0%

18.3% 29.4%

U

9.5%

16.1% 26.0%

X

8.5%

12.1% 20.1%

17.3% 26.8%

Y

7.1%

8.2%