Study on Energy Output Structure and Damage Effect of Aluminized RDX-based Explosive
Supervisor:jiao qing jie xu geng guang
The damage effect of underwater weapon is based on the nternal pre-filled explosive and explosive energy release.The RDX-based aluminized explosives are widely equipped with naval weapon and got a substantial increase in underwater explosion effect.The energy release of RDX-based aluminized explosive was studied by means of experiments with different quality and numerical simulation.This paper also studied aluminum second reaction from three aspects: explosive formulation,aluminum content and target response.This paper focuses on the following three aspects:(1)Underwater explosion experiments were conducted to determine the optimal performance of theRDX/Al explosives with an aluminum powders content of 0%,15%,and 30%.Free-field blast output energies of the three types of explosives were measured between 0.3 and 0.8 m.The shock wave energy,bubble energy,detonation energy,and thermal losses were measured.A new calculation method was based on the experimental results to simulate the bubble pulse process and pressure changes inside the bubbles of nonideal explosives.The specific distance at which maximum total energy was achieved for the underwater explosion was determined.(2)Aluminum powders are used in composite explosives as a typical reducing agent for improving explosion performance.To understand energy release of aluminum in aluminized RDX-based explosives,a series of thermal measurements and underwater explosion(UNDEX)experiments were conducted.Lithium fluoride(LiF)was added in RDX explosives,as a replacement of aluminum,and used in constant temperature calorimeter experiments and UNDEXs.The influence of aluminum powder on explosion heat was measured.A rich supply of data about aluminum energy release rate was gained.There are other oxides(CO2,CO and H2O)in detonation products besides alumina when the content of RDX is maintained at the same levels.Aluminum cannot fully combine with oxygen in the detonation products.To study the relationship between the explosive formulation and energy release,pressure and impulse signals in underwater experiments were recorded and analyzed after charges were initiated underwater.The shock wave energy,bubble energy and total energy monotony increase with the Al/O ratio,while the growth rates of the shock wave energy,bubble energy and total energy become slow.(3)The damaged assessment of aluminized explosive to the vesseltarget is an important evidenceof checking whether the formula is reasonable.The aluminized RDXbased explosives(RDX/Al)commonly used in mine and torpedo.In order to study the influence ofthe molar mass of aluminum and oxygen(the Al/O ratio)on vessel damage,the energy release of explosives and the damage to the vesselare studied in this paper in numerical simulations.The vesseldamage effect is explained from four aspects: stress,strain,displacement and acceleration.Simulation results show that the overall damage effect and the local damage effect of a vesselincreased to the max and then decreasedwith the the Al/O ratio increasedat the near field.The effect of explosive on vessel is the best when the Al/O ratio is 0.36.Combined with the relationship between the Al/O ratio and energy release rate,we draw a conclusion that the main reason for the damage of vessel is the shock wave energy in the near field.As can be seen from the target response,the rank order of explosive efficiency power is: JHL20(Al/O = 0.36)> JHL30(Al/O = 0.63)> JHL10(Al/O = 0.16)> JHL0(Al/O = 0).This is the same as the change of shock wave with the Al/O ratio.It can be seen that the shock wave can determine the damage effect of the explosive in near fieldIn this paper,three methods of test,simulation and theoretical study are used.The aluminum secondary reaction in aluminized explosives was studied in many aspects.It has a important significance upon aluminized explosive formulation optimization,improving the energy releasing of aluminized explosives in underwater explosion and increaseing the power of explosives.This paper also provides theoretical and numerical basis for the near ship targets attacking.