Dynamic Analysis And Failure Models Of Reticulated Shell Under Strong Earthquake

In recent years, the development of the space structure is very fast. Many space buildings have become the artistic works. With the advantages of reasonable mechanics,big span and graceful sculpt, reticulated shells which are one of the main forms of the space structure are widely applied in such cases as gymnasiams, departure halls of airport, and Convention and Exhibition Centers, etc. These structures are often of high safety level, the failure of which may cause huge lose of properties and even human's live.Research about the static performance of spatial structure today has made great achievements, the basic theory is quite mature. But the dynamic performance, especially the mechanical properties under earthquake, is still in the developing and perfecting stage. Therefore, the seismic performance should be studied carefully for long-span spatial structures. Under strong earthquakes, the reticulated shells may appear suddenly, and when it happens, the plastic deformation is very limited, the structural stiffness is almost as same as before and the displacement are not considerable. reticulated shells may strength failure, and when it happens, the plastic deformation is large, the structural stiffness is very large. And between the dynamic instability of single-layer latticed sphere shells have been failure and strength failure.In this passage, take single-layer reticulated shell and Qing Yang gymnasiam in Gansu province as study background. Nonlinear finite element method is applied. A dynamic characteristic and failure model will be analyzed by using finite software of ANSYS programs. The mainly work in this paper as follows:(1). First of all, modal analysis was carried on the K8 type of the net shell with different rise-span ratio 1/3, 1/5 and 1/7. Then, by changing rise to span ratio, the vibration characteristics of the shell and the vibration characteristics of structure considering the influence of geometric stiffness under static constant load were summarized.(2). Based on the modal analysis, Based on the structure response analysis method in Ansys, considering multi-indexes responses from macroscopic leves ,a large number of parameter analyses for single-layer latticed sphere shell have been done, which can be used for exploring the failure mechanism under strong earthquake. After the analysis of some typical cases the failure modes and some characteristics have been determined. (3). According to the research of the K8 shell, Modal analysis was carried on the shell of an actural project, Qing Yang gymnasium. And based on the results of the modal analysis, dynamic time-history analysis was carried on the shell, the dynamic performance of the shell under the action of earthquake was also discussed.