Dynamic Response Analysis Of Dual-direction Beam String Structure Under Explosion Load And Antiknock Research

Dual-direction beam string structure belongs to a new type of hybrid structure. It is the semi-rigid structure between the rigid structure and the flexible structure. This kind of structure has the following advantages:light weight, strong bearing capacity, simple construction, good equilibrium and stability, beautiful structure, etc. Current studies on the long-span spatial structure analysis under explosion shock load mainly focus on single layer spherical lattice shell structure, cylindrical lattice shell structure and double-layer spherical reticulated shell structure. There are few studies on dual-direction beam string structure roof grid under explosion shock load. Because the buildings of dual-direction beam string structure tend to be crowded public places, they often become the target of terrorist attacks. However, the influence of explosion shock load is rarely considered in the design of long-span dual-direction beam string structure. Nor is the anti-knock security capacity of the structure considered. But once explosions occur in the population intensive buildings of such structure, they will cause great economic losses and casualties. Therefore, it is necessary to study the dynamic response and the properties change rules of the dual-direction beam string structure under explosion shock load in order to improve the anti-knock security capacity of this structure.Through establishing the simulation model of explosive explosion in the air, according to comparing the overpressure peak values of different distance from explosive with those of empirical formula under the same condition, we prove that it is correct to apply LS-DYAN/ANSYS software to numerical simulation analysis. According to the propagation law of explosion shock wave, this paper expounds the various material parameters of air, high explosive, the member bar and roof sheathing of dual-direct ion beam string structure. It also conducts the dynamic response analysis of dual-direction beam string structure under explosion shock load. The paper mainly studies the explosions at different heights above the center of the dual-direction beam string structure, and the member bar stress condition and stress characteristic when the positions of the initiation point change laterally above the center of the structure. According to explosive similar law, we deduce the empirical formula of overpressure peak value of dual-direction beam string member bars under explosion shock load, sum up the stress change rule of the member bar when dual-direction beam string structure is under the eccentric action of explosive shock load. On this basis, we analyze and compare the condition of dual-direction beam string structure under the explosion shock load with the stress condition of spherical lattice shell structure, then analyze the stress characteristic of dual-direction beam string structure.Based on the study of dual-direction beam string structure roof sheathing under explosion shock load, the paper puts forward such antiknock methods as reinforce the member bar's strength, change the roof sheathing material, reinforce the node strength, add damper in structure sliding support, design reasonable structure shape and layout planning, etc. to improve the antiknock performance of dual-direction beam string structure, providing reference for the antiknock design research in the future.