Research On The Energy Release Characteristics Of Al/PTFE Reactive Fragment Impact-induced Deflagration

In order to enhance the damage power of the missile,more and more research institutions start paying attention to the question of using reactive materials on the warhead.And reactive metal material is one of the best options,reactive fragment which is made by this material have the characteristics of mechanical strength of metals,chemical energy of high explosives and safety of inert materials at the same time.Those characteristics make the warhead more powerful and do no need to make a big change to the original structure design of the projectile when it has been used on the warhead.So it receives wide attention.Reactive fragment is the prefabricated fragment which is made by reactive metal materials.In experimental research,it is usually made into cylindrical or spherical projectile.Generally,the ingredient of reactive material has more than two kinds of metal powder or mixing metal powder with polymer powder.Preparation through high pressure compaction,low temperature vacuum sintering and other process methods.It has certain penetration capability.Only under the action of strong impact load,violent chemical reaction can occur and release a lot of heat.In the process of damaging the target,it not only have enough kinetic energy to penetrate the target,but also can explode inside the target,cause more damage to the target,the damage power is greatly or even leap over increased.This thesis will from the aspects of simulation experiments,theoretical analysis and numerical simulation to study the energy release properties of reactive materials.The main research content and results are as follow:1.The energy release experiment of high-speed reactive projectile impact quasi-closed reaction vessel was studied.The essence of this experiment is to simulate the real application of reactive fragments.This paper compares this experiment with the static explosion experiment of high explosive in a sealed container,analyzing the similarities and differences between the two experiments.The results show that the research methods of high explosive can also be applied to the reactive metal material.Combined with the characteristics of material and experiment,the experimental data of impact initiation of reactive projectile were interpreted and processed,and the relationship curve of reaction heat with time was obtained.2.The formula for calculating the reaction heat of reactive fragments is deeply analyzed.The formula which is used to calculate the reaction heat is based on certain assumptions,in order to verify the hypothesis,aiming at the phenomenon of pressure relief from the invasion hole,based on the theory of fluid flow in Laval nozzle,using mature theories to study similar phenomena,combined with the characteristics of the experiment itself,established a pressure relief model and verify the hypothesis.Moreover,combined with the pressure relief model and the quasi-static pressure model,establish a heat calculation model which including factors like pressure relief,heat transfer and so on,the calculation results are more accurate.3.A detailed numerical simulation demonstration is showed for the process of impact-induced deflagration of Al/PTFE reactive fragment.Basing on Autodyn simulation platform,lead-in Powder Burn EOS,establish a computational model for impact initiation of reactive fragments.Results show that the simulation results can better match the characteristics of impact-induced deflagration of reactive fragments,the effect of destructive can be enhance by using reactive materials.The analysis and research methods in this paper will be of great significance to the design of reactive fragments,weaponization application,damage power evaluation and numerical simulation.