In current guidelines,the free air blast loads(overpressure and impulse)are determined by spherical charges,although most of ordnance devices are more nearly cylindrical than spherical in geometry.This may result in a great underestimation of blast loads in the near field and lead to an unsafe design.However,there is still a lack of systematic quantitative analysis of the blast loads generated from cy-lindrical charges.In this study,a numerical model is developed by using the hydrocode AUTODYN to investigate the influences of aspect ratio and orientation on the free air blast loads generated from center-initiated cylindrical charges.This is done by examining the pressure contours,the peak over-pressures and impulses for various aspect ratios ranged from 1 to 8 and arbitrary orientation monitored along every azimuth angle with an interval of 5°.To characterize the distribution patterns of blast loads,three regions,i.e.,the axial region,the vertex region and the radial region are identified,and the propagation of blast waves in each region is analyzed in detail.The complexity of blast loads of cylin-drical charges is found to result from the bridge wave and its interaction with primary waves.Several empirical formulas are presented based on curve-fitting the numerical data,including the orientation where the maximum peak overpressure emerges,the critical scaled distance beyond which the charge shape effect could be neglected and blast loads with varied aspect ratio in arbitrary orientation,all of which are useful for blast-resistant design.

Chu Gao;Xiang-zhen Kong;Qin Fang;Jian Hong;Yin Wang

State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact,Army Engineering University of PLA,Jiangsu,Nanjing,210007,China;Inner Mongolia University of Finance and Economics,Inner Mongolia,Hohhot,010070,China;Engineering Research Center for Safety and Protection of Explosion&Impact of Ministry of Education,Southeast University,Jiangsu,Nanjing,211189,China

防务技术

[1]Chu Gao;Xiang-zhen Kong;Qin Fang;Jian Hong;Yin Wang-.Numerical investigation on free air blast loads generated from center-initiated cylindrical charges with varied aspect ratio in arbitrary orientation)[J].防务技术,2022(09):1662-1678

ordnance,hydrocode

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