Effect Of Solid Content On Shock Wave Initiation Of Modified Double Propellant

The modified double-base propellant refers to the propellant with solid oxidant,high energy explosive,metal fuel and other components added to the propellant with nitrocellulose and nitroglycerin as the double base to improve the energy performance.It has a series of advantages such as high energy,high density,low characteristic signal,excellent combustion performance,good chemical stability,mature manufacturing process,easy to achieve mass,uniformity and consistency,and free filling.Howeve,due to the addition of some high-energy explosive components,the danger level is relatively high,which has a certain impact on the production safety,so it is necessary to study the safety performance of high-solid content modified double-base propellant.Therefore,this topic reveals the relationship between solid content and shockwave initiation characteristics of modified double-click propellant through two research methods:experiment and numerical simulation.To provide certain technical support for safety performance evaluation of modified double-base propellant,the main research content of this topic is as follows:First of all,the critical bulkhead thickness of shock wave priming for four kinds of modified double-base propellants with different solid contents of 54.6%RDX,46%RDX,18%RDX and without RDX was tested by using the large bulkhead shock wave sensitivity test method.The corresponding critical bulkhead thickness values are 23.76 mm,20.28 mm,15.26 mm and 10.13 mm,respectively.At the same time,the critical bulkhead thickness of three different solid contents of 40%HMX,21%HMX and modified double-base propellants without HMX was tested,and the corresponding critical bulkhead thickness values were17.76 mm,7.79 mm and 4.18 mm,respectively.Through the above tests,the influence law of solid content of RDX or HMX on shock wave initiation characteristics was revealed,and the quantitative equation of relationship between solid content of RDX or HMX and the critical partition thickness of shock wave initiation was obtained.Secondly,AUTODYN finite element simulation software was used to simulate the shock wave detonation characteristics of four different solid contents of 54.6%RDX,46%RDX,18%RDX and the modified double base propellants without RDX.The main procedures include the construction and design of models and the selection of different model parameters according to the respective model parts.Among them,JWL equation of state parameters were used for the main propellant column passive RDX material,John-Cook material constitutive model parameters were used for both separator and witness plate materials,and different binomial ignition growth equation parameters were used for modified double-base propellant materials with different solid contents.After the final calculation,the range of the critical diaphragm thickness value was obtained according to the curve of shock pressure variation and reactivity variation.The numerical simulation results were in agreement with the critical diaphragm thickness value obtained from the shock sensitivity test of large diaphragm,which effectively verified the scientific nature of the test data.Finally,the shock wave pressure values of the output shock wave of standard donor(passivated RDX)were tested by the Mn-Cu pressure sensor method after being attenuated by the separators of cellulose triacetate fatty sheets with different thicknesses.The attenuation law of shock wave pressure in the separators of cellulose triacetate fatty sheets was revealed,and the attenuation law relationship between the two was obtained by fitting.According to the attenuation law relation,the law and relation relation between solid content in modified double-base propellant and the critical pressure of shock wave initiation were obtained,and the influence law of solid content on the shock wave initiation characteristics of modified double-base propellant was revealed.