Study On Impact Energy Release Characteristics And Damage Effect Of Reactive Damage Element

High efficiency damage has always been the goal of weapons and ammunition.Because of the unique coupling damage effect of the reactive damage element,it not only has kinetic energy killing effect,but also can achieve thermal damage effect by releasing chemical energy.Therefore,the reactive damage element has been widely used in weapon equipment.At present,a large number of studies have been carried out on the impact energy release characteristics of the reactive damage elements,but the quantitative evaluation of the damage effect of the supporting reactive damage elements,the construction of the characterization parameter system of the impact energy release reaction process and combustion phenomenon,and the theoretical calculation considering the terminal thermal damage effect are relatively few.In view of this background,this paper comprehensively considers the relationship between the impact energy release behavior of reactive materials and their dynamic mechanical properties,taking typical aluminum/Polytetrafluoroethylene Composites and tungsten zirconium alloy type amorphous energetic fragments as the research objects,mainly using the method of combining theoretical analysis and experimental research,The dynamic mechanical behavior of the impact energy release process and the construction and quantitative analysis of the characteristic parameter system were carried out.The main research contents and achievements are as follows:（1）The shock energy release characteristics and damage law of reactive damage element are analyzed theoretically,and a theoretical analysis model suitable for transient combustion damage is established.Based on the burn through damage phenomenon of reactive damage element,the process of reactive energy release is divided into four stages:impact energy release,penetration energy release,post target energy release and secondary energy release.The characteristics and typical phenomena of each stage are analyzed theoretically,and the thermal damage effect behind the target is estimated quantitatively.Based on the existing fireball thermal radiation model,the key damage parameters in fireball evolution are determined,and the basis of parameter selection in the model is analyzed.（2）One dimensional impact loading experiment of metal fluoropolymer composites was carried out by using split Hopkinson pressure bar.The critical strain rate is about 1200s^-1,and the critical energy release rate is about 13m/s.The reactive material goes through the elastic compression unloading stage,and the strain rate is positively correlated with the reactive energy release in the plastic deformation stage.When the loading pressure is between 0.16MPa and 0.18MPa,the reactive material changes from excited state to combustion state;When the loading pressure is between0.3MPa and 0.35Mpa,the reactive material changes from combustion state to deflagration state.Based on the principle of equivalent energy release of reactive materials when the strain rates are equal,the relationship between the initial velocity of impact bar and the initial velocity of fragments hitting the target in the Hopkinson pressure bar experiment is derived theoretically.Through the quantitative analysis of the typical images of the impact energy release process,it is found that the combustion time of the reactive fragments is positively correlated with the initial velocity of the impact rod and the mass of the reaction part,and inversely correlated with the air contact area;There is a linear relationship between the maximum height of combustion flame and the initial velocity of pressure bar.（3）Two kinds of reactive fragments,metal fluoropolymer and tungsten zirconium alloy,were taken as the research objects.The ignition mechanism of metal fluoropolymer on cotton and oil tank and the effect of penetrating and expanding hole were analyzed.It was found that the penetrating hole diameter of the reactive fragment was more than twice of the fragment diameter.The main form of perforation was plug failure.The phenomenon of perforation delamination was obvious and the hole was oval.The pressure distribution behind the target is close to that of the quasi-static closed vessel,and the pressure value is mostly below one atmosphere.When the initial velocity is above 1110m/s,the overpressure value behind the target is close to two atmospheres.When the reactive fragments ignite the flammable solid target behind the target,there is a coupling damage effect of heat radiation and heat conduction,and the secondary energy release after the target has an important impact on the target damage.Through theoretical analysis,considering the experimental data and numerical simulation results,the influence rules of target material,thickness and initial velocity on the energy release reaction of the reactive material are obtained.It is found that the initial velocity of the target has a great influence on the energy release reaction after the target.Based on the quantitative analysis of high-speed image of ballistic gun,a parameter quantitative processing method considering the relationship between different stages of random process is proposed.The change rules of area change rate and maximum size change rate of energy release reaction region with time in different reaction stages are obtained,which are in good agreement with the experimental phenomena.In addition,the experimental results verify the correctness and feasibility of the theoretical calculation to a certain extent.