## 4 Structural Performance Optimization of Storage Tank
### Optimization Process of Structural Performance Parameters
\begin{table}
\begin{tabular}{c c c c c c c c} \hline No. & \(d\) & \(n_{x}\) & \(n_{y}\) & \(n_{z}\) & \(T\) & \(D\) \\ \hline
1 & 0.5 & 11 & 11 & 11 & 0.3 & 2 \\
2 & 0.6 & 12 & 12 & 12 & 0.35 & 2.5 \\
3 & 0.7 & 13 & 13 & 13 & 0.4 & 3 \\
4 & 0.8 & 14 & 14 & 14 & 0.45 & 3.5 \\
5 & 0.9 & 15 & 15 & 15 & 0.5 & 4 \\
6 & 1.0 & 16 & 16 & 16 & 0.55 & 4.5 \\
7 & 1.1 & 17 & 17 & 17 & 0.6 & 5 \\
8 & 1.2 & 18 & 18 & 18 & 0.65 & 5.5 \\
9 & 1.3 & 19 & 19 & 19 & 0.7 & 6 \\
10 & 1.4 & 20 & 20 & 20 & 0.75 & 6.5 \\
11 & 1.5 & 21 & 21 & 21 & 0.8 & 7 \\ \hline \end{tabular}
\end{table} 
Table 7: Parameter-level table for the improved storage structure with a square column structure. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline No. & \(d\) & \(n_{x}\) & \(n_{y}\) & \(n_{z}\) & \(T\) & \(D\) & \(\sigma\) & \(v\) & \(m\) \\ \hline
1 & 2 & 8 & 8 & 4 & 4 & 11 & 1142 & 96.974 & 259 \\
2 & 9 & 10 & 5 & 1 & 3 & 5 & 998.9 & 88.498 & 620 \\
3 & 6 & 9 & 2 & 10 & 9 & 9 & 286.7 & 91.911 & 552 \\
4 & 1 & 2 & 6 & 11 & 5 & 4 & 1251 & 98.165 & 224 \\
5 & 7 & 3 & 9 & 3 & 8 & 2 & 340.6 & 92.519 & 511 \\
6 & 5 & 6 & 1 & 6 & 1 & 1 & 1169 & 95.134 & 299 \\
7 & 3 & 5 & 4 & 2 & 11 & 7 & 992.4 & 97.241 & 343 \\
8 & 4 & 11 & 11 & 7 & 7 & 6 & 544.5 & 92.841 & 483 \\
9 & 10 & 1 & 3 & 5 & 6 & 10 & 167.5 & 91.152 & 544 \\
10 & 11 & 7 & 7 & 8 & 10 & 3 & 105 & 82.421 & 985 \\
11 & 8 & 4 & 10 & 9 & 2 & 8 & 295.3 & 88.333 & 614 \\ \hline \end{tabular}
\end{table} 
Table 8: Uniform test table and the calculation and finite element analysis results for the improved storage structure with a square column structure. We use 1 stOpt software to optimize \(\sigma\), \(v\), and \(m\), where the detailed optimization settings are shown in Table 10. When \(\sigma\), \(v\), and \(m\) are set to the target values, we can obtain the values of each parameter. According to the orders of the six factors affecting \(\sigma\), \(v\), and \(m\), and in order to facilitate the processing, modelling, and calculation for the final printing, the final value of each parameter is selected to be equal or greater than the optimal value of each parameter. The optimal values are listed in Table 11. The optimization process, optimization results, and calculation results are shown in Figures 7-9, respectively. According to the analysis results, the relative deviations of compressive stress, volume utilization rate, and weight between the optimization results and calculated results are 9.72%, 2.94%, and 4.15%, respectively. It has been demonstrated that the established regression equation can predict the structural performance of the improved storage tank. \begin{table}
\begin{tabular}{c c} \hline \hline
**Optimization Algorithm** & **Levenberg-Marquardt** \\ \hline Convergence judgment index & 1 \(\times\) 10–10 \\ Maximal iterated algebra & 10,000 \\ Real time output control number & 5000 \\ Times & 200 \\ Control iteration algebra & 300 \\ Convergent judgment algebra & 15 \\ \hline \hline \end{tabular}
\end{table} 
Table 10: The optimization settings. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Factor** & \(p\)**Value for \(\sigma\)** & \(p\)**Value for \(\sigma\)** & \(p\)**Value for \(m\)** \\ \hline Length (\(d\)) & 0.011 & 6.359 \(\times\) 10\({}^{-4}\) & 6.512 \(\times\) 10\({}^{-4}\) \\ Structure numbers in \(x\) direction (\(n_{x}\)) & 0.656 & 0.071 & 0.073 \\ Structure numbers in \(y\) direction (\(n_{y}\)) & 0.236 & 0.116 & 0.117 \\ Structure numbers in \(z\) direction (\(n_{z}\)) & 0.154 & 0.092 & 0.089 \\ Wall thickness (\(T\)) & 0.1 & 0.559 & 0.043 \\ Connecting distance to the side wall (\(D\)) & 0.321 & 0.465 & 0.462 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: The analysis results of \(p\)Figure 8: Volume utilization ratio optimization process, optimization results, and calculation results. Figure 7: Compression stress optimization process, optimization results, and calculation results. Figure 9: Weight optimization process, optimization results, and calculation results.