The Most Adverse Position And Design Method For Single-layer Cylindrical Reticulated Shell Under Internal Explosion

Large-span spatial structures suffer terrorist attacks because they are often used in public buildings.Because of the large number of people in public buildings,it is very important to study explosion-proof methods because of the large number of people who will be killed or injured in the event of a terrorist attack.Taking single-layer cylindrical reticulated shell as the research object,and the numerical simulation analysis of the structure is carried out with ANSYS/LS-DYNA.The dynamic response of the structure under the action of internal explosion is studied,and the key position of the structure is determined.At last,some suggestions for explosion-proof design are put forward.The main contents of the study are as follows:(1)The propagation law of internal explosion shock wave in single-layer cylindrical reticulated shell is analyzed.Because the single-layer cylindrical reticulated shell is different in the direction of span and the direction of longitudinal span,it is necessary to analyze the over pressure cloud images in both directions when analyzing the propagation law of internal blast shock wave.The results show that the propagation law of shock wave is different in the direction of span and longitudinal span.If the explosive explodes at the center of the structure,the shock wave will produce three times aggregation effect at the center of the shell top structure.(2)The dynamic response of single-layer cylindrical reticulated shell under the action of internal explosion is analyzed,and the shell-top node with larger displacement and the shell-top member with larger axial force are determined,and then by changing the equivalent of explosives,the initiation height of explosives is determined.The stiffness of the connecting member is used to further analyze the dynamic response of the structure.The results show that:(1)The increase of explosive equivalent is proportional to the node displacement and the axial force of the rod.(2)The nodal displacement and the axial force of the member are negligibledue to the initiation height.(3)The displacement of most joints is inversely proportional to the stiffness of the connecting member,while the axial force of the member is almost unaffected by the change of the stiffness of the connecting member.(3)The damage degree of single-layer cylindrical reticulated shell enclosing structure under internal explosion is analyzed,and a criterion for defining the failure grade of retaining structure is put forward.Then,the failure grades of roof slab and wall slab under three different working conditions are classified.Finally,the optimal location of the structure is determined.(4)Finally,some suggestions on explosion-proof design of long-span space structure are put forward based on the study of the previous chapters in this paper.This paper provides a systematic idea and solution to the different degrees of damage caused by implosion in actual engineering.