Blast Loading And Resistance Of Firework Factory Structure Under Confined Double-Explosives

The blast of fireworks factory has two features: On the one hand,the burst in the fireworks factory is a confined explosion;On the other hand,there are two explosives in the fireworks factory.The researches about the blast load of confined double explosives are limited for domestic and international.In this paper,we researched the blast loading and structural response under confined double explosions,and proposes a new method to evaluate the resistance of the fireworks factory.This evaluate method can apply to the real project.The main contents conclude:(1)We simulated the blast under double explosions in free air by Explicit dynamic analysis software LS-DYNA,and analyzed the objective rule of the shock wave propagation.It is concluded that: There are some interaction between the two shock waves,and the interaction will enhances the blast loading by 89.7%.With the increase of the distance between the two explosions,the area of Mach reflection is unchanged,and the degree of enhancement is correspondingly weakened.(2)We simulated the blast under confined double explosions in fireworks factory by Explicit dynamic analysis software LS-DYNA.The distribution of blast loading on the walls are as follows: the distribution of explosive loads along the walls is extremely non-uniformly,and there are two peak areas,which are located in the Mach reflect area and the corner area respectively.(3)There are two weaknesses of the existing method which used the existing standards:1.It is assumed that the blast loading is uniformly along the wall;2.The method only determining the blast loading of a single explosive.It is not suitable for determining the blast loading of confined double explosives.Considering the above factors,the walls of fireworks factory are divided into 9 zones,proposes the concept of enhancement factor,determining the enhancement factor of each wall area by the multi-point integration method.A new method for determining the blast loading of confined double explosives is proposed.(4)Based on the method of determining the blast loading of the confiend double explosives in this paper,we analyzed the dynamic response of the fireworks factory structure,and the evaluation method of resistance of the fireworks factory is improved.Under the confined double explosions of 7.0kg equivalent TNT equivalent,different bending deformation occur on the walls of the structure.The deformation of the back wall is the most serious,and the maximum deformation is located in the mid-span of each wall.The maximum displacement of the back wall is 76.7 mm,and the remnant displacement is 27.6 mm.The structure is slightly damaged.Because of the Mach reflection enhancement effect,the maximum deformation of the side wall located on its Mach reflection region,and there is also a large deformation in the mid-span region.