Study On Failure Mechanism For Kiewitt-lamella Under Two-point Symmetric Internal Explosion

Kiewitt-lamella reticulated shell has been widely used in large-scale sports facilities in recent years due to the advantages of the Kiewitt reticulated shell and the Lamella shell.But because of the staff-intensive,social concern,frequent use and other characteristics,resulting in security is weak,easy to become the target of terrorist attacks.In the context of severe international and domestic violence,anti-explosion research on Kiewitt-lamella reticulated shell is very necessary.In this paper,firstly,the numerical simulation method is used to analyze the collision of the shock wave and verify the correctness of the numerical simulation.Secondly,the numerical model of the reticulated shell is established,and the dynamic response of the structure is established.Failure mechanism and failure criterion are studied,and the corresponding explosion protection method is put forward.The main research contents include:(1)The method of numerical simulation is used to study the near-ground two-point synchronous explosion,and the numerical simulation is verified by the explosion test.The results show that the ??·O?????? formula is suitable for the calculation of the shock wave over-pressure at the intersection of the collision surface and the ground intersection.The J·Henry formula is suitable for the calculation of the over-pressure of the synthetic wave in the other surface of the collision surface.For the collision surface,The maximum over-pressure value in the height direction corresponds to the increase of the distance between the two explosive points.The average error of the shock wave over-pressure and the empirical formula is 20.89%The average error with the numerical simulation results is 17.31%.(2)The structural numerical model considering the strain rate effect of the material was established by ANSYS / LS-DYNA explicit dynamic program.The over-pressure distribution of the shock wave under the symmetrical internal explosion was studied.The height of the column and the shock wave near the reticulated shell were reduced and the increase of the distance between the two fried spots and the increase of the distance between the two fried spots.The over-pressure value near the crust of the impact wave increases first and then decreases,which is similar to that inthe air explosion.The increase of over-pressure near the reticulated shell is more close to the center of the reticulated shell than the effect of over-pressure.The height of the column is different from the top of the column.(3)Considering the influence of gravity,the dynamic response of Kiewitt-lamella reticulated shells under symmetrical internal explosion is analyzed with the distance between two burst points,plate thickness and vector-span ratio as parameters.The results show that the dynamic response of the structure increases first and then decreases with the increase of the distance of the two burst-point.The larger the thickness of the plate,the more intense the dynamic response and the decrease with the increase of the thickness.The larger the influence,the greater the vector response.(4)The failure criterion of the structure of the envelope,the displacement of the reticulated shells,the internal energy of the reticulated shell structure,the structural plasticity development and the structural damage are established.Based on the analysis of a large number of parameters,the Kiewitt Four failure modes of the-lamella reticulated shell: no damage,minor injury,moderate damage and severe injury.(5)Based on the failure example,the explosion-proof and anti-explosion design of the Kiewitt-lamella reticulated shell structure under symmetrical internal explosion is discussed.The main explosion-proof and anti-explosion methods are proposed,including strengthening the stiffness of the joint shell Kiewitt reticulated part of the ability to break down,strengthen the beam,the column components,the use of large vector to improve the structure than the explosion-proof capacity.