Research On Dynamic Response And Resist Blasting Performance Of Single-Layer Latticed Shell Under Internal Explosion

In this paper,numerical simulation is used to study the dynamic response and resist blasting performance of single-layer latticed shell subjected to the explosion of a typical suitcase bomb,getting the reticulated shell response characteristics and vulnerable weak parts at the most unfavorable type of internal explosion.Based on the remaining bearing capacity index,the post-explosion reticulated shell structure was evaluated for damage,and the damage factor expression of a single-layer reticulated shell under the action of a typical suitcase bomb explosion was obtained.On this basis,the damage geometric model of the reticulated shell was extracted,with reference to the "civil building reliability appraisal standard",which is not suitable for continued carrying,the safety class and rehabilitating opinions of the reticulated shell structure under different working conditions are given.The main research results of this paper are as follows:(1)Under the explosion of the suitcase bomb,the accumulated shock wave at the support of the shell,along with the propagation of the cover of the shell to the center of the shell,has a larger area of interaction with the ring rods at the same moment,resulting in a higher plastic strain percentage of the ring rods,and the closer to the ring rods of the support,the greater the axial stress,the lower the material’s redundancy.(2)Different locations of blasts,the flow field distribution inside the shell,the shock wave propagation path and the interaction process between the shock wave and the reticulated shell are quite different.Therefore,with the change of blasting location,the characteristic response changes significantly,and the response of each characteristic reaches an extreme at approximately 3/4 of the lattice shell’s half-span.(3)Under the explosion of suitcase bombs,the vulnerable of the latticed shell mainly consist of three parts.That is to say,the partial reinforcement effect of the shock wave causes the rods part and the column foot part near the shell support,and the ring rods part of the shell part caused by the influence of the shock wave propagation path.(4)Under the explosion of the suitcase bombs,the security level of the reticulated shell after explosion can be roughly divided into 3 levels according to the horizontal position of the blast point.That is,the Asu class within [0m-2.5m],the Bsu class within(2.5m-12.5m),and the Csu class within(12.5m-17.5m).Among them,there are differences in the distribution characteristics of the low security grade members(12.5m-17.5m).When the actual restoration is reinforced,the eccentricity of 15.0m should be taken as the critical point,and the areas with key reinforcements should be selected.