Stability And Collapse Mechanism Of Single-layer Spherical Reticulated Shell Structure Under Wind Load

The single-layer spherical reticulated shell structure is a typical large-span space structure,and its structure is relatively flexible.When subjected to strong wind,the dynamic response of the single-layer spherical reticulated shell structure is very significant.The structure may be damaged,collapsed,and damaged—threats to the safety of people’s lives and property.Therefore,the dynamic stability performance of the single-layer spherical reticulated shell structure has caused extensive research at home and abroad.However,the present research mainly focuses on the harmonic load,impact load,and earthquake loads.The relevant research on the dynamic stability performance under the action of string is limited.The wind resistance design parameters of the single-layer spherical reticulated shell structure in the Load Code for The Design of Building Structures are not perfect.Some studies use the body shape coefficient of the arched roof in the Load Code for The Design of Building Structures to calculate the wind-induced response of the single-layer spherical reticulated shell structure,which is bound to deviate from the actual results.In addition,there are few studies on the dynamic collapse of the single-layer spherical reticulated shell structure.The dynamic collapse of the single-layer spherical reticulated shell structure,the cause and development of the collapse need to be further studied.In order to explore the influence of different values of the body shape coefficient on the dynamic stability of the structure and the cause and development process of the dynamic collapse of the structure,the linear filtering method(AR autoregressive model)is used to simulate the wind speed time history on the single-layer spherical reticulated shell structure.Based on the incremental dynamic analysis method,the following studies were carried out using ANSYS finite element analysis software:(1)Firstly,the critical load and failure mechanism of single-layer spherical reticulated shell structure were compared and analyzed when the body shape coefficients were taken from the "Load Code for The Design of Building Structures" and "Standards for Wind Loads on Roof Structures." The resluts show that when the body shape coefficients taken from "Load Code for The Design of Building Structures" the wind resistance of the structure will be overestimated;under the "Wind Load Standard for Roof Structures," the plastic region of the reticulated shell structure first appeared in the central region and gradually developed from the central region to the peripheral region.Therefore,in such structures design,the body shape coefficient should be taken according to the "Standards for Wind Loads on Roof Structures," and the strength of the rods in the central area should be appropriately strengthened.(2)The influence of parameters such as dead load,rise-span ratio,height-span ratio,and other parameters on the dynamic stability of the structure is systematically analyzed when the body shape coefficient is taken from the " Standards for Wind Loads on Roof Structures." The results show that increasing the dead load will improve the dynamic stability performance of the structure,but the extent of improvement is very limited;when the rise-span ratio is 1/6 the dynamic stability performance of the structure is the best;the increases with the height-span ratio,the decrease of the dynamic stability performance of the structure;the damping ratio and the type of support have little effect on the dynamic stability performance of the structure;the dynamic stability performance of the structure when the lower support is considered is lower than that when the lower support is not considered.(3)Considering the geometric nonlinearity,material nonlinearity,and contact nonlinearity of the structure,the plastic follow-up strengthening model in ANSYS/LS-DYNA software is used to simulate the fracture behavior of the member.The physical quantities such as the deformation of the structure,the internal force of the member and the typical node displacement under the action of the structure are used as reference indicators.The results show that the main reason for the failure of structural members is the failure of the members after being subjected to a large axial tensile force under the reciprocating action of wind load.The rods in the central area of the structure firstly be destroyed.After the rods destroyed,the rods around the destroyed rods are under the combined action of the tearing caused by the unloading of the failed unit and the sudden increase in the axial tension during the redistribution of the internal force of the structure when the rods are destroyed.Successive failures are followed by structural collapse.Therefore,the strength of the rods in the central area of the single-layer spherical reticulated shell structure can be strengthened in practical engineering.