## 4 Verification
### Distorted Model II  
This section aims to validate the similarity when dealing with distorted model II, which involves stiffener configuration distortions through the substitution of flat bars  
Figure 15: Acceleration and displacement time history curves of reference model and distorted model I. (**a**) Uncorrected group (acceleration); (**b**) corrected group (acceleration); (**c**) uncorrected group (displacement); (**d**) corrected group (displacement). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**No.** & **Results** & **Unit** &
\begin{tabular}{c} **Reference** \\ **Model** \\ \end{tabular} & **Model 1** & **Model 2** & **Model 3** & **Model 4** & **Model 5** \\ \hline Uncorrected & Plastic displacement & mm & 39.41 & 43.63 & 40.89 & 38.37 & 36.65 & 35.31 \\ Group & Difference & - & - & 10.72\% & 3.77\% & \(-\)2.62\% & \(-\)7.00\% & \(-\)10.40\% \\  & Peak acceleration & mm/s\({}^{2}\) & 202,301 & 184,551 & 196,695 & 206,696 & 217,748 & 227,705 \\ \hline Corrected & Difference & - & - & \(-\)8.77\% & \(-\)2.77\% & 2.17\% & 7.64\% & 12.56\% \\ Group & Plastic displacement & mm & 39.41 & 39.78 & 39.70 & 39.51 & 39.75 & 39.63 \\  & Difference & - & - & 0.95\% & 0.75\% & 0.27\% & 0.88\% & 0.57\% \\  & Peak acceleration & mm/s\({}^{2}\) & 202,301 & 198,136 & 201,432 & 203,220 & 205,054 & 205,238 \\  & Difference & - & - & \(-\)2.06\% & \(-\)0.43\% & 0.45\% & 1.36\% & 1.45\% \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Loading cases of distorted model I.  
for the original T-type stiffeners. Extending the distorted model outlined in Table 7, the corresponding distorted model was designed, featuring flat-bar stiffener configurations. Additionally, the impact blocks used in these models maintain the same geometric attributes as those of the distorted models I, featuring a radius of 80 mm and being subjected to a consistent initial impact velocity of 3 m/s. Adhering to the criteria outlined in Section 3.3, the precise dimensions of the flat-bar stiffeners were determined to fulfill Criterion 1. The heights and thicknesses of the flat-bar stiffeners are adjusted to maintain a consistent static moment and sectional area of the integrated stiffener sections with the corresponding distorted models I. For instance, considering model 2 from Table 7 as an illustrative example, the associated distorted model II, denoted as M2-E, was designed with a flat-bar stiffener measuring 46.93 mm \(\times\) 1.22 mm, signifying a height of 46.93 mm and a thickness of 1.22 mm. The static moment and sectional area of the integrated stiffener section in M2-E amount to 1396 mm\({}^{3}\) and 153.26 mm\({}^{2}\), respectively, closely approximating the values exhibited by the corresponding stiffener in model 2 (1396.97 mm\({}^{3}\) and 153.25 mm\({}^{2}\)). A schematic depicting distorted model II M2-E, along with its accompanying impact block, is illustrated in Figure 16. The detailed dimensions and load cases of each distorted model (corresponding to the distorted model) are listed in Table 10. It is noted that the impact mass applied in each distorted model II is the same as the corresponding distorted model I due to the similar sectional area, as illustrated in Section 3.3. The simulation cases were set up with the same boundary conditions and contact restrictions as those used for distorted model I. The maximum final plastic displacement and peak acceleration during impact for each model are listed in Table 11. Although the numerical results of the corresponding distorted model I are concluded in Table 9, they are included in Table 11 for reference purposes. In addition, Figure 17 presents the acceleration and displacement history curves, with solid lines denoting the reference models and dashed lines representing the distorted models.