## 3 Results and Discussion  
It should be noted that the practical results presented above were obtained through the sequential passage of the evaluation stages indicated in the \"Materials and Methods\" section, starting with the \"Reverse Engineering-Style Research Framework\" where the algorithm for solving a typical problem is described as given, and ending directly \"Practical Framework Application\". It is recommended that the results be presented by the key objectives of the research and that the strength and safety parameters of the model be consistently investigated in accordance with R100 and the requirements of the customer (bus manufacturer). Objective 1: to evaluate stress concentration and plastic deformation behaviour of battery mounting structures under R100 loading conditions. When analysing stresses, there is no question whether they will remain within the material linearity according to Hooke's law. Unambiguously, there will be zones of plastic deformation, where \(\sigma_{max}>\sigma_{y}\): for example, max von Mises stress is 376.7 MPa in transverse 10 g mode (\"2-10g-L\" in Figure 4a) and 426.85 MPa in longitudinal 12 g mode (\"2-12g-F\" in Figure 4b). The mode with the highest local stress is \"3-12g-B\" with 12 g acceleration applied in the back longitudinal direction. It has received \(\sigma_{max}\) = 439.08 MPa at \(t_{cmax}\) = 0.1 s (Table 2), although the average stress \(\sigma_{ave}\) = 56.29 MPa, which is not the highest among the studied modes: the maximum \(\sigma_{ave}\) is obtained in the \"2-12g-B\" mode--83.18 MPa. It should be noted that none of the \(\sigma_{max}\) results reached the tensile strength of S235 steel (360 MPa). Element-by-element analysis of the model allows for selecting the optimal steel grades, for example, S275 for increased stresses (over 275 MPa) and reducing the cost, since the structure is collapsible (bolted). \begin{table}
\begin{tabular}{c c c c c c c c} \hline
**Mode** & **Acceleration** & **Direction** & \(\sigma_{max}\)**, **MPa** & \(t_{e_{max}}\)**, **ms** & \(\sigma_{ave}\)**, **MPa** & \(t_{e_{max}}\)**, **ms** & \(\delta\)**, **mm** \\ \hline
1-10g-L & 10 g & left & 423.88 & 100.00 & 61.48 & 50.00 & 58.13 \\
1-10g-R & 10 g & right & 366.50 & 41.50 & 42.23 & 50.50 & 22.78 \\
1-12g-F & 12 g & front & 375.16 & 34.00 & 62.24 & 50.00 & 58.76 \\
1-12g-B & 12 g & back & 394.05 & 15.50 & 52.54 & 50.00 & 27.83 \\
2-10g-L & 10 g & left & 376.87 & 26.50 & 46.26 & 50.20 & 19.64 \\
2-10g-R & 10 g & right & 385.80 & 48.00 & 48.95 & 50.00 & 24.68 \\
2-12g-F & 12 g & front & 426.85 & 48.50 & 81.71 & 50.20 & 57.37 \\
2-12g-B & 12 g & back & 390.23 & 34.00 & 83.18 & 50.60 & 63.04 \\
3-10g-L & 10 g & left & 364.89 & 39.00 & 40.90 & 50.00 & 6.95 \\
3-10g-R & 10 g & right & 371.71 & 36.00 & 43.02 & 50.40 & 7.95 \\
3-12g-F & 12 g & front & 426.24 & 100.00 & 55.03 & 50.00 & 16.94 \\
3-12g-B & 12 g & back & 439.08 & 100.00 & 56.29 & 50.00 & 18.07 \\ \hline \end{tabular}
\end{table} 
Table 2: Results of the simulation of battery units in Ansys transient structural simulation according to UNECE R100. In addition to the stress values in the unit model itself (Figure 4), the reactions in the places of the bolt fasteners (Table 3) are a question of interest--they determine what forces will be transmitted to the original bus body (whether they are permissible) and what grades of bolts are recommended. The pre-calculated maximum shear load on an M10 bolt from a hardware guide is 1494 kg (14,651 N), considering the 5.6 grade. Thus, increasing the number of bolt holes and using M12 (max shear load is 20,947 N) with a higher grade (at least 8.8-10.9) is suggested. The graphs (Figure 5a-c) show dense fluctuations of \(\sigma_{max}\) during the period of 0-0.05 s, which corresponds to the zone of acceleration growth according to the graph of Figure 2.  
Figure 4: [PERSON] stress maps of the battery unit #2 in the following modes: (**a**) “2-10g-L” (left pulse direction); (**b**) “2-12g-F” (front pulse direction).