## 5 Discussion
### Criterion 3 for Prototype with an Intermediate Stiffener Web Height
Previous research indicates that prototypes with intermediate web height stiffeners tend to be web thickness-dominant. Consequently, the recommended value of the ratio \(P_{1}/P_{cr-e}\) for the various prototypes should be related to the corresponding web thickness. In this context, distorted models featuring flat-bar stiffeners, characterized by a web thickness of 1.15 mm and web heights ranging from 70 to 90 mm, were subjected to simulations. Table 19 provides detailed information on the dimensions and analytical results of the ratio \(P_{1}/P_{cr-e}\) for these models. In this empirical investigation, the load case remains consistent across all simulations, involving an impact mass of 0.4 t and an impact velocity of 3.0 m/s. The corresponding numerical results are summarized and compared to RP-T47 (black solid line) and are presented in Table 19 and Figure 28. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No.** & **Item** & **Unit** & **RP-T47** & **RP-T47-E** & **RP-T47-T** \\ \hline Specim & Attached plate thickness & mm & 640 \(\times\) 340 & 640 \(\times\) 340 & 640 \(\times\) 340 \\  & Attached plate thickness & mm & 1.3 & 1.3 & 1.3 \\  & Stiffener & mm & \(\pm\frac{47.15\times 15}{15\times 150}\) & 61.24 \(\times\) 1.25 & 66.57 \(\times\) 1.15 \\  & Sectional area & mm\({}^{2}\) & 180.6 & 180.6 & 180.6 \\  & Static moment & mm\({}^{3}\) & 2409.8 & 2409.2 & 2613.4 \\ \hline Load Case & \(M_{\rm I}\) & t & 0.4000 & 0.4000 & 0.4000 \\  & \((v_{0})_{d2}\) & m/s & 3.0 & 3.0 & 3.0 \\ \hline Results & Plastic displacement & mm & 38.27 & 37.20 & 38.54 \\  & Difference & - & & \(-\)2.79\% & 0.71\% \\  & Peak acceleration & mm/s\({}^{2}\) & 191,251 & 202,924 & 206,736 \\  & Difference & - & & 6.10\% & 8.10\% \\ \hline \hline \end{tabular}
\end{table} 
Table 18: Relevant geometrical parameters and results (_RP-_T47-_related). Figure 27: Comparison between distorted and reference models (RP-T47-_related). (**a**) Acceleration; (**b**) displacement. Hence, it is recommended that the distorted model T115-H80, characterized by a ratio \(P_{1}/P_{cr\text{-}e}\) of 4.58, aptly represents the dominant behavior within the intermediate range of the ratio \(P_{1}/P_{cr\text{-}e}\), spanning from 1.55 to 3.21, when the web thickness is 1.15 mm (see Table 16). Furthermore, by simplifying the sectional properties, the ratio \(P_{1}/P_{cr\text{-}e}\) was inferred to be proportional to \(h_{\text{w}}^{3}/t_{\text{w}}^{2}\). Under the identical procedure, the most suitable distorted model for the three supplementary groups of intermediate-stiffened plates reference models with consistent web thicknesses of 0.9 mm, 1.0 mm, and 1.1 mm were examined with various web heights. As a result, the minimum difference from the reference model was obtained by the web heights of 78 mm, 79 mm, and 80 mm, respectively, for the web thicknesses of 0.9 mm, 1.0 mm, and 1.1 mm, revealing a consistent trend in web height, primarily ranging from 78 to 80 mm, as shown in Figure 30. The blue square scatter represents the web height, and the blue circle scatters represent the ratio \(P_{1}/P_{cr\text{-}e}\) of the most suitable distorted model across these groups. Therefore, owing to the insensitivity of the web height in the previous group, the ratio \(P_{1}/P_{cr\text{-}e}\) of the suggested distorted model was assumed to depend on the inverse square of the web thickness (\(1/t_{\text{w}}^{2}\)).