# Structural Design and Optimization of Separated Air-Rib Tents Based on Response Surface Methodology
## 6 Conclusions  
The air-rib tents are widely used because they are lightweight and site adaptable, but the large deformation of these tents reduces their effective space. It is significant to reduce the displacement of the air-rib tent by parameter optimization. Four external parameters of the tent's wind ropes, which are studied in the paper, are the angle of the wind ropes, the number of the wind ropes on the side, and the initial prestress of the wind ropes on the side or end faces. The effect of the wind rope on the Von Misses stress and the displacement under load is studied by the finite element method, and the response surface methodology is used to minimize the displacement of the tent. The results are only applicable to the specific geometry and the size of the tent. The tents of other sizes and structures will be optimized in the future.  
The effect of the wind ropes on the maximum displacement of the tent is stronger than that on the Von Misses stress of the tent under the external load. The angle of the wind ropes and the number of the wind ropes on the side are the two most significant parameters which affect the displacement of the tent. With the increase in the angle, the displacement of the tarpaulin increases at first, and then decreases. The minimum displacement appears when the angle of the wind ropes is \(41.5^{\circ}\). The closer the wind ropes are added to the center of the tarpaulin, the greater the displacement of the tent is. The influence of the number of the wind ropes on the maximum displacement under load is nonlinear.  
Based on the analysis using the response surface methodology, the relationship between the angle of the wind ropes and the number of the wind ropes on the side is significant. The effect of the angle of the wind ropes on the maximum displacement of the tent decreased with increasing the number of the wind ropes on the side. The optimal parameters are as follows: the angle of the wind ropes is \(41^{\circ}\), the number of the wind ropes on the side is two, the initial prestress of the wind ropes on the end face is \(800\) Pa, and the  
Figure 13: The simulation results of the tent in the optimal conditions. (**a**) The displacement of the tarpaulin; (**b**) the displacement of the air ribs; (**c**) the Von Misses stress of the tarpaulin; (**d**) the Von Misses stress of the air ribs.  
initial prestress of the wind ropes on the side is 0 Pa. In the condition with the optimal parameters, the maximum displacement reduces by 10.2%, and the maximum stress barely changes.  
It can be concluded from the results that the external factors have a significant effect on the maximum displacement of the tent. The maximum displacement can be reduced by changing the angle of the wind ropes and the number of the wind ropes on the side, if the structural parameters of the tent are fixed. The best values of the external factors can be used to increase the effective space of the air-rib tents.  
Conceptualization, Y.L. and Y.R.; methodology, J.Z.; software, Y.L. and Y.R.; validation, Y.L. and Y.R.; formal analysis, Y.L. and Y.R.; investigation, L.Z., S.L. and X.C.; resources, F.L. and J.Z.; data curation, Y.R.; writing--original draft preparation, Y.R.; writing--review and editing, Y.L. and S.L.; visualization, Y.R.; supervision, F.L., L.Z., J.Z. and X.C.; project administration, L.Z. and J.Z.; funding acquisition, J.Z. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Open Research Fund Program of Beijing Engineering Research Center of Monitoring for Construction Safety, grant number BJC2020K011; Young Teachers' Research Ability Enhancement Program Project of Beijing University of Civil Engineering and Architecture, grant number X21059.  
Not applicable.  
The authors declare no conflict of interest.