Dynamic Stability And Seismic Vulnerability Analysis Of Long Span Reticulated Shell Structures Under Multi-dimensional Excitation

At the moment when the requirements for building space are getting higher and higher,the large-span reticulated shell structure has rapidly developed into a typical spatial structure with a wide range of applications.At the same time,the large-span space reticulum is extremely complex under the action of ground motion,showing significant spatial mechanical characteristics,and the damage caused to the people's production and life once it is destroyed is often unbearable.Therefore,its seismic performance analysis under multi-dimensional ground motion has considerable practical and social significance.In this paper,the single-layer long-span spherical reticulated shell structure is taken as the research object.Based on the ABAQUS finite element analysis platform,the dynamic stability and seismic vulnerability under multi-dimensional excitation are analyzed.The large-span reticulated shell structure in each dimensional earthquake is studied.Differences in performance from specific seismic response to probabilistic seismic performance under dynamic excitation.Firstly,considering the influence of material nonlinearity and geometric nonlinearity,a large-scale reticulated shell structure model with a span of 60 m is established by ABAQUS,and the nonlinear analysis method,modal analysis method and ground motion of the reticulated shell structure are elaborated.The input and adjustment methods and the seismic analysis method of the structure under multi-dimensional excitation of ground motion.Then,considering the initial defects of the space reticulated shell,the El-Centro wave is used as the excitation ground motion,and the response and stability of the single-layer spherical reticulated shell structure of 60 m long span under one-dimensional,two-dimensional and three-dimensional earthquakes are analyzed.Comparing the critical load of structural dynamic instability under different seismic dimensions,the structural plastic rod proportion and displacement deformation map at the time of instability,the results show that seismic dimension is an important factor affecting the response of large-span reticulated shell structure and its failure process.The horizontal two-dimensional two-dimensional ground motion input is more reliable than the one-dimensional input calculation result,and is the minimum dimension required for seismic analysis of the large-span space reticulated shell structure.At the same time,the large-span reticulated shell structure is more likely to expose its own weak areas under the action of multi-dimensional earthquakes and sudden collapse damage.In the actual seismic design,multi-dimensional excitation can not be ignored under the action of strong earthquakes.The impact of the response.Finally,considering the influence of the double uncertainty of structure and ground motion on the seismic response of the structure,the seismic vulnerability analysis under IDA is performed on the 40 sets of structural-ground motion sample models with random composition,and the large-span reticulated shell structure is obtained.Probability vulnerability function and its seismic vulnerability curve and probability matrix under dimensional and 3D seismic excitation.The analysis results show the importance and necessity of multi-dimensional seismic excitation for seismic analysis of large-span reticulated shells from the failure probability level of the structure,and the large-span reticulated shell structure is very easy to be in itself under the one-dimensional or three-dimensional ground motion excitation.After the medium damage is exceeded,the serious damage stage is passed,and the structural collapse occurs directly.In the seismic design of the large-span reticulated shell,such damage should be avoided.