Stability Analysis And Anti-collapse Measures Of Large-span Space Reticulated Shell Structure Considering Damage Accumulation

In this paper,based on the ABAQUS finite element analysis software,taking the large-span space Kaiwitt reticulated shell as the research object,first considering the dual nonlinearity of geometry and material,the buckling behavior of the structure type under static load and the different members are analyzed in depth The static response of the structure under the conditions of cross-sectional strength,structural vector-to-span ratio,material initial defects,and bearing constraints at the bottom of the structure,it is found that when analyzing the static stability of the reticulated shell under static action,it is necessary to decompose as many such structures as possible Vibration mode,in order to comprehensively consider the combination of various buckling modes;drawing load-displacement curves can more clearly and intuitively express the influence of various structural parameters on the static stability performance,considering the geometric and material dual nonlinearity The calculation result is closer to the actual situation of the project;the sensitivity of the reticulated shell to the outer diameter of the component will be much higher than the wall thickness,so the cross-sectional strength of the component can be appropriately enhanced in the weak or vulnerable areas of the reticulated shell structure;The increase in the structure will significantly improve the static stability of the structure under static load;the reticulated shell structure is a defect-sensitive structure.The initial defects of the structure decrease and increase in sequence,but the increasing trend is getting slower and slower;the type and number of restraints at the bottom of the structure have very little effect on the ultimate bearing capacity of the reticulated shell,but after the number of restraints of the support is halved,The structural instability is more obvious.Then introduce the material damage model,derive the Rayleigh damping coefficient calculation formula,analyze the difference of the dynamic response of this type of reticulated shell under different dimensional seismic waves,and study that the reticulated shell under the frequent earthquakes,only X-directional seismic wave The dynamic response index can be used as the main basis for engineering design safety.However,under rare earthquakes,due to the complexity of the three-dimensional seismic wave's dynamic response to the structure,comprehensive consideration of the three-dimensional seismic wave is more in line with the actual situation.Based on the incremental dynamic analysis(IDA)method,the dynamic response of the structure when the micro damage of the material is considered is reduced by about 20% compared with that without consideration,and the proportion of the plastic element is increased by about 10%;the initial geometric defects after the damage are considered to make the dynamic response of the reticulated shell The maximum reduction is about 30%;after the number of bearing constraints at the bottom of the structure is halved,the cumulative effect of material damage reduces the dynamic response of the structure by about 10%;during the finite element simulation,it is found that the yield element and the maximum node displacement of the structure almost all occur In the first to fourth rings of the reticulated shell structure,it is concluded that the collapse of the Kaiweite reticulated shell is often caused by material damage at the weak parts of the structure until the structure collapses,so the weak links of the structure need to be strengthened.From the previous research,it is concluded that the weak parts of the structure under static and dynamic loads are mainly concentrated in the first to fourth rings at the bottom of the structure,and various strengthening measures and optimal solutions are proposed for the weak parts.The results show that directly strengthening the strength of the cross-section of the bar can improve the ultimate bearing capacity of the structure,and the cross-section of the inclined bar that strengthens the weak part of the reticulated shell has a better effect on improving the seismic resistance of the reticulated shell than the ring bar.The anti-seismic effect of the structure is much greater than that of the double layer of the ring rod;when the viscous damper is used,the "replacement" method has a better damping effect than the "additional" method.In addition,for different building structures,there is an optimal damping Coefficient;different installation schemes of buckling restraint support have different effects on the seismic reduction effect of the structure,and the collapse resistance of the reticulated shell under the optimal scheme can be increased by 13.3%.