为综合分析爆炸成型弹丸(explosively formed projectile,EFP)的构型对其气动特性和侵彻性能的影响,实现兼具良好气动特性和侵彻性能的EFP设计。开展了EFP的成型和飞行试验,在试验验证数值有效性的基础上,基于任意拉格朗日欧拉(arbitrar...为综合分析爆炸成型弹丸(explosively formed projectile,EFP)的构型对其气动特性和侵彻性能的影响,实现兼具良好气动特性和侵彻性能的EFP设计。开展了EFP的成型和飞行试验,在试验验证数值有效性的基础上,基于任意拉格朗日欧拉(arbitrary Lagrange-Euler,ALE)算法分析了后翻型EFP的三种典型构型(实心杆状、小空腔状、大空腔状)的成型过程及气动特性,并进一步开展了三种构型EFP侵彻半无限厚45#钢的数值模拟。结果表明:EFP小空腔结构提高了其飞行稳定性;空腔的增大降低了EFP的存速能力,实心、小空腔、大空腔三种构型的EFP炸高在1000倍弹径(30 m)时平均速度降分别为158 m/s,172 m/s,210 m/s;随着EFP空腔的增大,靶板开坑形貌由漏斗状逐渐转为等直径状。从工程实践角度设计EFP构型时:对于近距离目标应选取实心型;对于远距离目标应选取小空腔型。展开更多
为达成快速精准预测爆炸成型弹丸(explosively formed projectile,EFP)速度以及检验校准JWL状态方程参数等目的,使用LS-DYNA有限元软件建立Φ65 mm EFP的数值模型,研究JWL状态方程各参数对EFP速度的影响规律。在此基础上,拟合建立基于JW...为达成快速精准预测爆炸成型弹丸(explosively formed projectile,EFP)速度以及检验校准JWL状态方程参数等目的,使用LS-DYNA有限元软件建立Φ65 mm EFP的数值模型,研究JWL状态方程各参数对EFP速度的影响规律。在此基础上,拟合建立基于JWL状态方程参数的EFP速度计算公式,构建EFP速度的BP神经网络预测模型,生成学习样本对网络模型进行训练。结果表明,JWL状态方程参数对EFP速度存在显著影响,参数R_(1)影响最大,各参数影响的大小顺序为R_(1)、A、B、R_(2)、E_(0)、ω;计算公式和网络模型均能够精准预测EFP速度,网络模型的预测精度优于计算公式,其中计算公式的结果误差绝大部分能够控制在10%以内,网络模型的预测误差均不超过5%。展开更多
To quickly break through a reinforced concrete wall and meet the damage range requirements of rescuers entering the building,the combined damage characteristics of the reinforced concrete wall caused by EFP penetratio...To quickly break through a reinforced concrete wall and meet the damage range requirements of rescuers entering the building,the combined damage characteristics of the reinforced concrete wall caused by EFP penetration and explosion shock wave were studied.Based on LS-DYNA finite element software and RHT model with modified parameters,a 3D large-scale numerical model was established for simulation analysis,and the rationality of the material model parameters and numerical simulation algorithm were verified.On this basis,the combined damage effect of EFP penetration and explosion shock wave on reinforced concrete wall was studied,the effect of steel bars on the penetration of EFP was highlighted,and the effect of impact positions on the damage of the reinforced concrete wall was also examined.The results reveal that the designed shaped charge can form a crater with a large diameter and high depth on the reinforced concrete wall.The average crater diameter is greater than 67 cm(5.58 times of charge diameter),and crater depth is greater than 22 cm(1.83 times of charge diameter).The failure of the reinforced concrete wall is mainly caused by EFP penetration.When only EFP penetration is considered,the average diameter and depth of the crater are 54.0 cm(4.50 times of charge diameter)and 23.7 cm(1.98 times of charge diameter),respectively.The effect of explosion shock wave on crater depth is not significant,resulting in a slight increase in crater depth.The average crater depth is 24.5 cm(2.04 times of charge diameter)when the explosion shock wave is considered.The effect of explosion shock wave on the crater diameter is obvious,which can aggravate the damage range of the crater,and the effect gradually decreases with the increase of standoff distance.Compared with the results for a plain concrete wall,the crater diameter and crater depth of the reinforced concrete wall are reduced by 5.94%and 9.96%,respectively.Compared to the case in which the steel bar is not hit,when the EFP hit one steel bar and the intersection of two steel bars,the crater diameter decreases by 1.36%and 5.45%respectively,the crater depth decreases by 4.92%and 14.02%respectively.The EFP will be split by steel bar during the penetration process,resulting in an irregular trajectory.展开更多
本文研究了高可靠度小型EFP(Electronic Field Production)系统方案在会议全媒体直播中的应用。首先,对小型EFP系统和高可靠度设计原则进行了概述,分析了会议全媒体直播系统的需求。并提出了一种高可靠度小型EFP系统设计方案,包括系统...本文研究了高可靠度小型EFP(Electronic Field Production)系统方案在会议全媒体直播中的应用。首先,对小型EFP系统和高可靠度设计原则进行了概述,分析了会议全媒体直播系统的需求。并提出了一种高可靠度小型EFP系统设计方案,包括系统架构、功能模块和应急处理方案。在此基础上,将该系统应用于会议全媒体直播系统设计中并进行了测试和评估。展开更多
本文以庆祝澳门回归祖国20周年大会直播为例,解析了户外超高清EFP视频系统架构,介绍了CGTN频道通过4K EFP系统完成电视节目直播的系统搭建方案。应用了圆偏振镜(Circular-Polarizing Lens,CPL)和摄像机主站的RCP(Remote Control Panel)...本文以庆祝澳门回归祖国20周年大会直播为例,解析了户外超高清EFP视频系统架构,介绍了CGTN频道通过4K EFP系统完成电视节目直播的系统搭建方案。应用了圆偏振镜(Circular-Polarizing Lens,CPL)和摄像机主站的RCP(Remote Control Panel)控制面板技术参数配合有效改善画面质量的实践经验,是推进户外超高清直播系统普及应用的实践探索。展开更多
文摘为达成快速精准预测爆炸成型弹丸(explosively formed projectile,EFP)速度以及检验校准JWL状态方程参数等目的,使用LS-DYNA有限元软件建立Φ65 mm EFP的数值模型,研究JWL状态方程各参数对EFP速度的影响规律。在此基础上,拟合建立基于JWL状态方程参数的EFP速度计算公式,构建EFP速度的BP神经网络预测模型,生成学习样本对网络模型进行训练。结果表明,JWL状态方程参数对EFP速度存在显著影响,参数R_(1)影响最大,各参数影响的大小顺序为R_(1)、A、B、R_(2)、E_(0)、ω;计算公式和网络模型均能够精准预测EFP速度,网络模型的预测精度优于计算公式,其中计算公式的结果误差绝大部分能够控制在10%以内,网络模型的预测误差均不超过5%。
基金supported by the Scientific and Technological Innovation Project(Grant No.KYGYZB0019003)。
文摘To quickly break through a reinforced concrete wall and meet the damage range requirements of rescuers entering the building,the combined damage characteristics of the reinforced concrete wall caused by EFP penetration and explosion shock wave were studied.Based on LS-DYNA finite element software and RHT model with modified parameters,a 3D large-scale numerical model was established for simulation analysis,and the rationality of the material model parameters and numerical simulation algorithm were verified.On this basis,the combined damage effect of EFP penetration and explosion shock wave on reinforced concrete wall was studied,the effect of steel bars on the penetration of EFP was highlighted,and the effect of impact positions on the damage of the reinforced concrete wall was also examined.The results reveal that the designed shaped charge can form a crater with a large diameter and high depth on the reinforced concrete wall.The average crater diameter is greater than 67 cm(5.58 times of charge diameter),and crater depth is greater than 22 cm(1.83 times of charge diameter).The failure of the reinforced concrete wall is mainly caused by EFP penetration.When only EFP penetration is considered,the average diameter and depth of the crater are 54.0 cm(4.50 times of charge diameter)and 23.7 cm(1.98 times of charge diameter),respectively.The effect of explosion shock wave on crater depth is not significant,resulting in a slight increase in crater depth.The average crater depth is 24.5 cm(2.04 times of charge diameter)when the explosion shock wave is considered.The effect of explosion shock wave on the crater diameter is obvious,which can aggravate the damage range of the crater,and the effect gradually decreases with the increase of standoff distance.Compared with the results for a plain concrete wall,the crater diameter and crater depth of the reinforced concrete wall are reduced by 5.94%and 9.96%,respectively.Compared to the case in which the steel bar is not hit,when the EFP hit one steel bar and the intersection of two steel bars,the crater diameter decreases by 1.36%and 5.45%respectively,the crater depth decreases by 4.92%and 14.02%respectively.The EFP will be split by steel bar during the penetration process,resulting in an irregular trajectory.
文摘本文研究了高可靠度小型EFP(Electronic Field Production)系统方案在会议全媒体直播中的应用。首先,对小型EFP系统和高可靠度设计原则进行了概述,分析了会议全媒体直播系统的需求。并提出了一种高可靠度小型EFP系统设计方案,包括系统架构、功能模块和应急处理方案。在此基础上,将该系统应用于会议全媒体直播系统设计中并进行了测试和评估。
文摘本文以庆祝澳门回归祖国20周年大会直播为例,解析了户外超高清EFP视频系统架构,介绍了CGTN频道通过4K EFP系统完成电视节目直播的系统搭建方案。应用了圆偏振镜(Circular-Polarizing Lens,CPL)和摄像机主站的RCP(Remote Control Panel)控制面板技术参数配合有效改善画面质量的实践经验,是推进户外超高清直播系统普及应用的实践探索。
