Numerical Simulation Analysis On Internal Explosion Accident Of Crane Girder In A Steel Factory

Along with the development of urbanization, confined space exists widely inpublic transit system, warehouse, firecracker factory etc, which are closely bound upwith daily life, and where explosion accidents occur frequently. In May2012, therehappened an explosion accident of a crane girder in a steel factory in Shaoguan,Guangdong, causing casualties and different degrees of damage of facilities around.As a kind of metal sealed construction, the crane girder has different internalexplosive characteristics. It is necessary to analyze the explosion accident process ofthe crane girder and to discuss the unknown explosion reason and the TNT equivalentof unkown explosive source.High energy explosive was used instead of the unknown explosive source in thisarticle to study the failure process of the crane girder under internal blast load, and thespread process of blast wave inside the crane girder. The major research methods andprocedure are as follows:(1) Numerical simulation test of explosion in air was carriedout by using the finite element software ANSYS/LS-DYNA. The results showed awell consistent with empirical formula, proving the reliability of model and materialparameter, and preparing for the anti-blast analysis of the crane girder.(2)The finiteelement computation model of the crane girder was established by usingANSYS/LS-DYNA. The failure strain of steels and TNT equivalent were adjustedwhen the numerical simulation results were in accordance with the actual damage ofthe crane girder. The failure strain of steel and the TNT equivalent will be thereasonable value when the results coincide with each other. The failure overallprocess of the crane girder was analyzed by picking up the stress, strain, anddisplacement data.(3) A numerical simulation was conducted to explore the influenceof TNT equivalent and blast location on the blast wave pressure distribution by usingANSYS/LS-DYNA.The following conclusions were obtained through the simulation analysis:(1) TheTNT equivalent of the unknown explosion resource in the crane girder accident is122.25kg.(2) The failure strain of the steel plate used in crane girder is0.35.(3) The blast waves spread along the steel plate inside the crane girder and accumulate in thecorner, the web and the lower cover plate of crane girder are welded by one-side filletweld with low strength, and the lower cover plate has large displacement response.All above are the reasons leading the crane girder failure mode.(4) It is helpful fordecreasing the failure of crane girder under blast load to increase the weld strength,steel failure strain, and to set stiffener.