Numerical Analysis And Design Method Of Net Type Blast Wall

Based on the principle that complex phenomena such as interference and diffraction can reduce energy when encountering obstacles in the process of wave propagation,Hao Hong and his team have carried out a series of studies on the "one-dimensional colume type" new fence wall composed of several individual structural columns,and its effectiveness in reducing explosive load has been demonstrated by field tests and numerical simulations.According to the existing research results of fence-type wall,a net type wall is proposed in this paper.By adding crossbars on the columes,forming a "two-dimensional plane" net-type structure,which takes into account the effect of complex interference and diffraction cancellation in two dimensions.In this paper,three-dimensional numerical simulation of net wall is carried out to study the change of explosion wave after interaction with longitudinal and transverse rods.The following four aspects of work have been carried out:(1)The explosion reduction effects of single-layer net type wall and multi-layer fence type wall are studied and compared.In AUTODYN,single-layer net wall and 1/2/3 fencetype wall are built,and the results of overpressure and impulse at the measured points behind the wall are compared and analyzed,and the explosion-reducing effects of different explosion-proof walls are obtained.The results show that the protective effect of singlelayer net-type wall is better than that of one-layer and two-layer fence type wall,and close to three-layer fence structure.It proves that the net-type wall has better interference and diffraction effect on explosion wave and the effectiveness of the model.(2)The explosion-proof effects of 13 kinds of reticulated explosion-proof walls with different layers and layers are studied and compared.The protective effect under 100 kg TNT equivalent is compared with the direction of explosion wave propagation and the overpressure and impulse on the surface of buildings.The results show that the staggered arrangement of the horizontal and vertical poles of the net type walls with different layers can achieve the best protective effect.(3)The distribution of overpressure and impulse on the surface of buildings is studied,and the calculation formula is fitted.Four parameters,TNT equivalent,combination form of network explosion-proof wall,distance from explosion center to network wall and height of building,are selected to study the influence of different parameters on the load distribution on the surface of building.Reflective overpressure and impulse data of calibrated points on the surface of rigid building are extracted from numerical simulation calculation,data processing is carried out,reasonable and simplified load curve is obtained,and load formula is carried out.Fitting provides the basis for the evaluation of explosive load and the design of explosion resistance of the buildings behind the net type wall.(4)The structural responses of new net type wall and traditional reinforced concrete solid wall under different equivalent TNT are studied and compared.The research shows that the reinforced concrete solid explosion-proof wall will produce high-speed debris under the action of equivalent TNT,which will cause secondary damage to the surrounding people,property and environment;and the protective effect of the optimized mesh explosion-proof wall is equivalent to or even better,and the steel has strong toughness.Under the action of explosion,the explosion-proof wall will only yield local steel and produce plastic deformation,and will not produce high-speed debris.This proves the superiority of the new mesh explosion-proof wall in structural protection.