Under The Explosive Shock Load Dynamic Response Of Blast-resistant Doors

In nowadays, with the spreading of terrorism, world peace and development remain thetheme of the era, terrorist attacks caused great harm to society’s peace and tranquility. So, Thestudy of dynamic response of structure under explosive loads is a concerned problem in theengineering field. This paper selected the commonly used steel structure Blast-resistant doorsas the research object, established finite element model. Analysis this structure underexploding shock of dynamic response. This article research work has two parts as follows:1、Without changing size of the door, material properties and so on, under the equivalentdistance of0.4, analysis the displacement, stress, strain, speed and energy, get the followingconclusion:（1）Displacement of blast-resistant doorsBecause the explosion shock loading time is shorter, the peak load is larger, thedisplacement of Blast-resistant doors continue increase along the movement directionvibration because of the effect of inertia force, arriving at the maximum displacement. Whenthe load time is longer, before the load disappeared the displacement is largest. Compared themaximum displacement2.7mm of the blast-resistant door node of the theoretical calculationwith the numerical simulation’s3.4mm, there is a difference0.7mm and the error is20%,which shows the calculated results obtained by numerical analysis and the theoretical resultsare consistent, and also explained the choice’s correctness of the finite element model unit andmaterial parameters.（2）Stress of blast-resistant doorsThe maximum stress first appeared at the edge of the blast-resistant doors, and then withthe increase displacement of blast-resistant doors, stress gradually expand to the center, Thestress of each node increases first and then decreases.（3）Strain of blast-resistant doorsDue to the short time of explosion shock load, after explosion shock loading, thespringback phenomenon will happen. So the strain time history curve has a increase decreaseprocess, finally form the residual deformation of the door. Compare different equivalent straintime history curve, the shorter of explosion shock loading time, the greater of the peak load,the greater of the peak strain and the larger of the residual strain. （4）Speed of blast-resistant doorsExplosion early, each special node of blast-resistant doors appeared negative velocityfirst, the larger the distance, the larger the speed peak, after reach the negative velocity peak,began to decrease, then reaches0, and increase the principal speed peak, also present areciprocating vibration. The whole speed of blast-resistant doors is less than the speed of thespecial nodes. Each special node of blast-resistant doors weak heavily than the wholeblast-resistant doors. The moment of maximum speed about special nodes and the wholeblast-resistant doors are coincided basically.（5）Energy of blast-resistant doorsThe total energy is equal to the sum of both kinetic energy and strain energy. In bothcases of the equivalent distance about0.4and0.6, the phenomenon of the kinetic energyincrease first and then decrease, finally the kinetic energy is zero. Strain energy and totalenergy also have this phenomenon.2、On the finite element dynamic simulation of blast-resistant doors, Change strength ofmaterials、thickness、steel keel, peak value and action time of explosion load and so on, thecalculation results show that：Although the result show that the larger effect of plate thickness,the little effect of the I-steel keel type, the material strength has smaller effect on themechanical properties. Consider the effect of economic factors, in order to improve theresistance deformation performance of blast-resistant doors, when use larger steel gradeI-steel keel, can get the highest economic benefits, enhance the strength of material get highereconomic benefits, while increase the plate thickness is not economic.Through a large number of numerical simulation, research the current commonly usedsteel structure blast-resistant doors about the dynamic response and characteristics, andanalysis the size of the influence factors. this paper has laid a solid foundation for laterresearch work, provide some reference material of antiknock under explosion impact loadcharacteristics and dynamic response of the blast-resistant doors of explosion-proof designresearch.