Analysis Of The Load-bearing Performance Of The Reticulated Shell Structure With Bending Member

Due to processing,manufacturing,installation and other reasons,the large-span reticulated shell structure inevitably has geometric defects such as node position deviation and curvature members.The reticulated shell structure is a defect-sensitive structure,and the geometric defects have a more complicated effect on the bearing performance of the reticulated shell structure.It is of great theoretical significance and practical engineering value to study the impact of geometric defects on the load-bearing performance of reticulated shell structures.This article takes the actual project of a large-span reticulated shell structure as a research object,based on the measured data on the structural layout,geometric dimensions,node displacement,and curvature members of the reticulated shell structure.Establish the reticulated shell structure model to analyze static bearing,stability ultimate bearing and seismic performance,etc.,mainly do the research in the following aspects:1.Static bearing analysis.The perfect model based on the original structure design and the defect model considering the curvature members were established respectively,and the structural displacement,member strength and stability calculation of the two structural models under various load conditions were carried out.The influence of the curvature members on the static bearing performance of the reticulated shell structure was studied.The results show that:compared with the perfect structural model,the maximum displacement of the nodes of the reticulated shell structure is increased by 14.7%,the internal force of the most unfavorable member is increased by 5.1%,and the overall rigidity of the reticulated shell structure and the bearing capacity of the member are affected.2.Stability limit load analysis.The uniform defect modal method is used to simulate the distribution of node position deviation defects and curvature members defects.A perfect model based on the original structure design,a defect model considering node deviation,and a defect model considering node deviation and curvature members are also established.Through the nonlinear stability limit load analysis of the three finite element models,the influence of the node position deviation defect and the curvature members defect on the stable bearing performance of the reticulated shell structure is studied;The path of the member that is destabilized during the loading process of the defect model considering both the node deviation and the curvature members is tracked,and then the mechanism of the instability of the reticulated shell structure after considering the influence of geometric defects is discussed.The results show that:the curvature defect of the members can reduce the bearing capacity of the lattice shell structure,so the curvature defect of the members should be paid attention to in the analysis of the structural stable bearing;The ultimate failure of the reticulated shell structure stems from the first instability of the bent rod.The instability of the rod will not lead to the sudden loss of the overall structural bearing capacity,and the internal force of the structure will be redistributed to continue bearing.3.Analysis of seismic performance.Under the action of 7-degree frequent earthquakes and rare earthquakes,the seismic performance of the above three finite element models was analyzed.By comparing the difference in displacement response and stress response of different reticulated shell models under various seismic waves,the effect of bending defects on the reticulated shell structure on seismic performance was studied.The results show that,under the action of different seismic waves,the maximum displacement of the node of the lattice shell model considering the node position deviation increased by about 17.5%,and the maximum stress of the member increased by about 12%,relative to the perfect structural model.Compared with the reticulated shell structure model that considers the node position deviation,the maximum displacement of the node is increased by about 11.8%,and the maximum stress of the member is increased by 4.3%.It shows that geometric defects can affect the dynamic response of the reticulated shell structure under earthquake load;With the increase of seismic acceleration,the influence of bending defects on the dynamic response of the lattice shell structure also increases.