مجله تحقیق و توسعه مواد پرانرژی
سال نهم شماره 1 (پیاپی 18، بهار 1392)

The investigation of the response of the munitionunder some specific mechanical or thermal stimulus is very important in order to determine the munition sensitivity is very important in development new munition. Insensitive Munition tests include: fast and slow cook-off test, fragments impact, bullet impact, shaped charge jet impact and sympathetic detonation.in this article, meanwhile define insensitive munition and description of response types of the munition to dangerous threats is investigated and in final effect of ageing on the munition sensitivity is explained.

After several years, Solid rockets in storage, due to physical and chemical process have been aged and under these conditions performance will largely fall. Because of the risks of keeping aged rockets in depot, solid propellants must be removed and using safe and green methods disposal them. Discharge and disposal of these aged propellants using traditional methods has hazards and environmental pollution. In this article have been investigated safe methods for remove and disposal grain of propellant and other hand some components recovery.

The aims of this paper are review the effects of Propellant Formulation parameters and improving an understanding of mechanisms of burn rate temperature sensitivity. The initial temperature of a solid propellant influences the burn rate, pressure and thrust of the propulsion system. The temperature sensitivity, σp of solid propellant burn rate directly affects the accuracy and performance of the rocket motor and thus low values of temperature sensitivity are essential in order to reduce the cost of the Missile/Armament systems and desirable performance. In this study, summary of fundamental mechanisms of solid propellants burn Rate temperature sensitivity are considered. The effects of propellant formulation variables on σp experimental data are considered. The experimental effects studied include: pressure, temperature, type of binder, aluminum content and size, AP content and particle size width distribution and additives including ferrocenes, carboranes, BEFP, copper chromite and iron oxide. For non-aluminized AP/inert binder propellants, σp is reduced when the AP size distribution is narrowed. Iron containing burn rate modifiers such as iron oxide, ferrocenes and BEFP are effective in lowering σp.

The double-base solid propellants normally include nitrocellulose, nitroglycerin and diphenyl amine (DPA) as energetic polymer, energetic plasticizer and stabilizer, respectively. Half-life of a gun double-base solid propellant containing these compounds was determined by accelerated aging method. Extraction of propellant stabilizer has been done by using a Soxhlet apparatus and dichloromethane solvent from aged samples at temperatures 55, 70 and 85 °C. Extracted samples were analyzed by high-performance liquid chromatography. The amount of DPA was measured in interval times 1000, 2000, 3000 and 4000 hours using HPLC method. Kinetic and Arrhenius equations showed a half-life of 14 months at 25 °C temperature for tested gun double-base propellant.

Today's military and non-military applications of energetic materials has grown substantially.Due to the risks associated with instability and thermal explosions of energetic materials is needed before production safetycharacteristics of them to be studied in a laboratory scale.In this work by using a differential scanning calorimetric(DSC) approach, it was tried to establish methods for deriving, analyzing and determining the parameters related to their instability and thermal explosion such as activation energy, pre-exponential constant, self accelerating decomposition temperature, critical temperature of thermal explosion, time required to reach the maximum rate, adiabatic temperature rising, explosion potential(EP), reaction hazard index(RHI), compatibility and incompatibility of the energetic materials with the other ingredients of the formulation. Introduce the complementary method. determination of activation energy and frequency factor that first be used the free model method for determination of activation energy.Then be compared this values with modelistic method. Be used a free model method(vyazovkin) for determination of, that this values be compared with modelistic method such as coat-redfern.then with this value of activation energy, other safety parameters can be determined.

Due to the importance of concrete structures, the field of projectile penetration into concrete targets has attracted increasing research efforts. Gao et al. presented a new method for penetration analysis into concrete targets. Propagation of shock waves due to impact is the base of this method. The aim of the present study is to investigate and modify this model. In this research, first a brief explanation of extracting Gao’s method formulas is provided. Then, the validity of the model results is investigated. Considering the errors and contradictions observed in this method, a modified model is introduced. This modification is done by developing a relation for distance between shock front and surface of projectile. By exploiting this modified model, the penetration depths and the instantaneous deceleration curves are calculated‬. In addition numerical simulations are performed by using the finite element code AUTODYN. Good agreement between numerical, experimental and analytical results can be observed.

Energetic materials specifically explosives material used extensively both for civil and military applications. Therefore probability explosion energetic material is unavoidable. The need to development of energetic materials with high performance and greater stability to heat, thermally stable explosives, is given priority in research development energetic materials, which are safer, more reliable and more stable in the world applications recently. In this paper in addition to introducing thermally stable explosives structure and theoretical reasons for this stability, process manufacture, their properties and their stabilizing, their advantages and disadvantages and heat-stable methods for explosive, has been investigated. Some of suitable candidates of this group have been presented and their synthesis have been evaluated. Sensitivity to impact and friction TATB Is introduced as a measure to study the thermal stability. Furthermore, this review also describes the synthesis and properties of BTDAONAB which does not melt below 550 °C and it is considered a better thermally stable explosive than TATB. Finally, future of research in this field in the years to come is also highlighted.