Research On Detonation Characteristics Of Fragmented Impacted Shelled TNT Charge

Natural fragment is an irregular fragment produced after the explosion of projectile.The randomness of the shape and box velocity of natural fragment brings difficulties to the study of the corresponding laws of impact initiation of natural fragment to explosive.In this paper,according to the grading standard of Fragment-Simulating Projectiles(FSP)put forward by the United States,the FSP used in this study is designed to study the threshold value and influence law of the impact of fragment simulation projectile on TNT naked charge and shell charge,The main contents of this paper are as follows:(1)According to the designed FSP,the ball shaped fragment,cylindrical fragment,hexagonal prism fragment and cube fragment with the same mass are designed.Based on the research conclusion of James and Cook,the theoretical velocity threshold of the other four fragments impacting TNT naked charge is calculated.At the same time,according to the theory of fragment impact with shell charge,and combined with Jabos Rouslund empirical formula,the theoretical velocity threshold of fragment impact with different shell thickness is calculated..(2)Using LS-DYNA software,the numerical simulation of five kinds of fragment impact TNT naked charge is carried out,and the simulation thresholds are obtained.According to the simulation results,the shape coefficient of FSP head and the initiation threshold of five kinds of fragment impact TNT naked charge are fitted,and the velocity threshold relationship between FSP and the other four kinds of fragment impact explosive is obtained.In order to study the influence of the simulated impact attitude of fragments on the initiation of TNT naked charge.By means of numerical simulation and experimental verification,the impact initiation TNT naked charge with 9g FSP in different target attitude is analyzed.The influence of FSP target attitude on TNT naked charge velocity threshold is obtained.The experimental results are in good agreement with the simulation and theoretical results.(3)On the basis of fragment impact TNT naked charge,the initiation characteristics of FSP impact TNT charge with shell were studied.According to the theoretical calculation results,the experimental research was carried out first,and the relevant parameters of fragment impact TNT charge with shell were obtained.Then,according to the theoretical calculation results and test results,the impact of 9g and 24 g FSP on TNT charges with different shell thickness was expanded by numerical simulation The results of numerical simulation are in good agreement with the theoretical results.