Study On Failure Mechanism And Vulnerability Of Single-layer Cylindrical Aluminum Alloy Latticed Shell Subjected To Severe Earthquakes

The reticulated shell structure is a large-span spatial grid structure with good mechanical properties and unique structural expressions.Among them,the reticulated shell structure exhibits excellent stress characteristics when an earthquake disaster occurs.With the development of China's economy and the advancement of science and technology,the large-span spatial structure has achieved rapid development and is widely used in large public buildings.The earthquake is a sudden natural disaster,and the human and economic losses caused by the earthquake are enormous.Therefore,it is especially important to carry out seismic design theory research and seismic safety risk assessment for reticulated shell structures.In recent years,China has achieved rich theoretical results in the study of seismic performance and failure mechanism of steel reticulated shell structures.As aluminum alloy materials are more and more widely used in large-span reticulated shell structures,the theoretical study on seismic behavior of aluminum alloy reticulated shell structures is particularly important.At present,there is little research on the related aspects of aluminum alloy reticulated shell structure.Therefore,based on the previous research in this paper,the failure mechanism and seismic vulnerability of single-layer cylindrical aluminum alloyreticulated shell structures under strong earthquakes are systematically studied.The main research contents are as follows:(1)Study on failure characteristics of aluminum alloy reticulated shells subjected to severe earthquakesFirstly,this paper uses the large-scale general finite element analysis software ABAQUS to establish the overall analysis model of the single-layer cylindrical aluminum alloy reticulated shell structure,based on the ABAQUS user subroutine(UMAT).The characteristic response analysis of aluminum alloy reticulated shells under strong earthquakes was carried out by incremental dynamic time history analysis(IDA).Then,the failure of single-layer cylindrical aluminum alloy reticulated shell structures was investigated by large-scale parametric analysis.The characteristics vary with different analysis parameters(aspect ratio,span ratio,roof quality,seismic wave,etc.).Finally,through the statistics of a large number of examples under strong earthquakes,the single-layer cylindrical aluminum mesh is mastered.Failure characteristics and variation of shell structure under strong earthquakes.(2)Study on failure mechanism of in single-layer cylindrical aluminum alloy reticulated shells under severe earthquakesFirstly,the variation of the characteristic response of single-layer cylindrical aluminum alloy reticulated shells under strong earthquakes is summarized.The whole process of failure characteristic response of single-layer cylindrical aluminum alloy reticulated shells with load amplitude is obtained.Two typical strong earthquake failure modes of class structure;secondly,based on fuzzy mathematics theory,the failure criterion of single-layer cylindrical aluminum alloy reticulated shell structure is established.Through the failure mode discrimination of a large number of examples,a single-layer cylindrical aluminum alloy is established.The failure mode discrimination method of reticulated shells;finally,based on the structural damage theory,the multi-feature response index of the reticulated shell structure strength failure time is fitted,and the strong earthquake damage factor of single-layer cylindrical aluminum alloy reticulated shell structure is fitted.A structural damage model with multiple failure signature responses.(3)Seismic vulnerability analysis of single-layer cylindrical aluminum alloy reticulatedshellsFirstly,the basic principle of structural seismic vulnerability analysis is expounded.The quantitative indicators for characterizing the damage degree of single-layer cylindrical aluminum alloy reticulated shell structure are investigated,and the performance level suitable for single-layer cylindrical aluminum alloy reticulated shell structure is established.Dividing method;Secondly,based on this,the typical single-layer cylindrical aluminum alloy reticulated shell structure is subjected to seismic vulnerability analysis,Monte Carlo simulation method is used to sample,a certain number of structural samples are generated,and 20 seismic waves are randomly selected.Forming the structure-ground motion sample pair;Finally,through the primary and secondary regression analysis of the result data,the seismic vulnerability function is established based on the seismic vulnerability analysis principle,and the seismic vulnerability of the single-layer cylindrical aluminum alloy reticulated shell structure is established.