# Structural Optimization of Combine Harvester Plate-Shell Undergoing Multi-Source Excitation
## 4 Conclusions  
1. In the multi-source excitation vibration environment, the structural factors that affect the forced vibration of the combine harvester plate and shell structure include the width, thickness, and position of the stiffened plate; the size of the hole, and the width of the edge stiffener. The closer the stiffened plate is to the excitation point, the better the restraint effect on vibration. By increasing the thickness of the stiffened plate, the multi-point excitation vibration response of the four-side clamped plate can be effectively controlled. By increasing the width of the stiffened plate, the vibration response of the multi-point excitation of the simply supported plate on four sides can be effectively controlled. The larger the hole in the plate, the larger its forced vibration response. By reducing the width of the stiffened plate, the response of the four-side clamped plate to the multi-point excitation forced vibration can be suppressed.
2. The effective optimization design of the combine harvester shell structure can be realized by using the Latin hypercube as the experimental design method, the Kriging model as the surrogate model, and the genetic algorithm as the optimization algorithm. Through the scheme of optimization, the width of the edge is optimized from 8 mm to 10 mm, the width of the stiffener is optimized from 25 mm to 7 mm, and the thickness of the foundation plate is optimized from 1.2 mm to 1.4 mm. The first-order natural frequency of the plate is improved, and the mass remains unchanged, avoiding the resonance range of the main excitation of the machine; at the same time, its dynamic response under the action of the multi-point harmonic force is also greatly reduced to 62.4%.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Modal** & **Fundamental Frequency of** & **Fundamental Frequency of** & **Correction** \\
**Order** & **Original Board** & **Optimized Plate** & **Correction** \\ \hline
1 & 88.08 & 100.95 & +14.6\% \\
2 & 114.48 & 140.29 & +22.5\% \\
3 & 140.21 & 157.62 & +12.4\% \\
4 & 163.54 & 178.03 & +8.9\% \\
5 & 171.52 & 201.27 & +17.3\% \\
6 & 210.88 & 213.61 & +1.3\% \\ \hline \hline \end{tabular}
\end{table}
Table 6: Comparison of the fundamental frequency of the board before and after optimization.  
**Author Contributions:** Conceptualization, Z.T.; Methodology, B.Z. and Z.T.; Validation, X.G. and B.Z.; Formal Analysis, X.G. and B.Z.; Data Curation, X.G. and B.Z.; Investigation, H.W. and H.Z.; Writing--Original Draft Preparation, Z.T. and X.G.; Writing--Review and Editing, X.G.; Supervision, B.Z. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research work was supported by Single Technology Research and Development Project of Jiangsu Agricultural Science and Technology Innovation Fund (CX (21)3144), Jiangsu Province \"Six Talents Peak\" High-level Talent Project (GDZB-085), Jiangsu Research and Practice Innovation Program Project (KYCX21_3382).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data used to support the findings of this study are available from the corresponding author upon request.  
**Conflicts of Interest:** The authors declare no conflict of interest.