Failure Modes And Design Optimization Of Light Steel Plant Enclosure Walls Subjected To Indoor Dangerous Chemical Explosion

Exploding accidents caused by dangerous chemicals occurred from time to time,bringing great losses to the nation's economy and people's safety.According to the investigation of accident scenes,light steel structures' disadvantages are exposed that they are vulnerable to explosions,especially for enclosure walls.Therefore,the failure modes of light steel structures' enclosure walls subjected to explosive load of hazardous chemicals and optimization of explosion-proof design methods should be studied urgently.In this dissertation,three main problems are studied.They are:(1)failure modes of light steel plants' enclosure walls subjected to explosion load;(2)the optimization of explosion-proof design of light steel plants;(3)the vented pressure of light steel plants subjected to indoor explosion and revision of the internal safety distance in hazardous chemical parks.More detailed introductions and major conclusions are presented as the following:(1)The finite element analysis software Ansys / Ls-dyna is used to build the enclosure wall model of light steel plant and to simulate its failure processes when subjected to explosions of different amounts of TNT at different distances.Based on their dynamic responses and energy conversion,failure modes of the sandwich wall panel are divided into three kinds and their transferring and dissipation processes of explosion energy are analyzed: the panel is detached from the structure and deforms in the middle as a whole;the core is so extruded that it is separated from face sheets and the panel begins to get torn and damaged at the bottom;the panel is severely damaged and local tearing failure is getting dominant.(2)Based on the failure characteristics of sandwich panels,an optimized method for designing the enclosure wall of light steel plants is put forward: moving the pair of cross bracings between columns outside the wall panel,making them function as explosion-proof bars by reinforcing the enclosure wall panels.The effects of various parameters on the failure modes and energy dissipation performances of sandwich panel under blast load are studied,such as the cross-sectional dimension of bracing,the thickness of core,the thickness of face sheets and the distance between self-drilling screws,etc.Recommendations on wall panel design and the positions where dangerous chemicals should place are proposed based on the results.(3)Using the fluid-solid coupling method to simulate the interaction between the blast shock wave and the wall panels,the distribution of shock wave outside structure is studied.Then the effects of various parameters on the shock wave distribution is analyzed,such as the distance between TNT and panel,the amount of equivalent TNT,the explosion-proof bracings,the design parameters of the sandwich panel,etc.Based on the simulation results,the internal safety distances of hazardous chemicals parks in the codes are revised.