Magiran | فصلنامه مواد پر انرژی، سال پنجم شماره 1 (پیاپی 9، بهار و تابستان 1389)

انتخاب همه

Improvement of the Production Efficiency of HBIW Using New Catalysts

Y. Bayat, S. Samy, M. Zarei Page 3

CL-20 is the most energetic conventional explosive available for military use. The overall aim of the high energy material research community is to increase yield and reduce cost of CL-20. All synthetic routes used to prepare the CL-20 depended on the condensation reaction of benzylamine with glyoxal for preparation of HBIW intermediate. In the presence of HCOOH as catalyst, yield of 75% is reported. In this paper we investigated the effect of lewis acid catalyst on the yield of HBIW. The results suggested that the more efficient catalyst (such as MgSO4, ZnCl2, CuSO4, Mg(ClO4)2 increase yield, 25% more than previously reported.

Abstract View Paper Original: Persian
Buckling Analysis of the Composite Warhead Under External Pressure and Axial Force

J. E. Jam, M. Heydari Page 11

In this study, the analysis, manufacturing and experimental buckling test of a composite warhead subjected to external pressure and axial load are investigated. Variation of angle and thickness along the none length are obtained, also the optimum filament winding design is achieved by considering minimum disordered patterns and wasting materials. In continue the static and buckling analysis of the composite warhead is performed using FEM software with Eigen value Analysis. The variation of the wound angle and the thickness are surveyed and the optimum angle is extracted. The composite warhead is manufactured based on the optimum angle. The process and equipments of the external pressure test are designed and the composite warhead is tested. The obtained buckling results of the FEM and the experimental are compared and also the efficiency of this method in prediction of buckling behavior of the composite warhead is demonstrated.

Abstract View Paper Original: Persian
Study of Heat Treatment Effect on the Synthesis of Boron Carbide Nano Particles via PVA and Boric Acid as Precursors

A. Fathi, N. Ehsani, H. Baharvandee, A. Alizade, A. Rahimnezhadyazdi Page 21

In this study, boron carbide nano particles have been fabricated with polymeric precursors. PVA (poly vinyl alcohol) and boric acid with constant weight ratio are composed together. In the next section, received materials have been pyrolized at 600-800°C, and then have been heated at 1400-1600°C. Products have been studied by FTIR for investigation of reaction mechanism. Particle size and crystalline form of Boron carbide nano particles was demonstrated by scanning electron microscope (SEM) images and X-ray diffraction patterns. Finally, boron carbide nano particles with 80-120 nm with good crystalline form are produced.

Abstract View Paper Original: Persian
Terminal Ballistic Design of Long Rod Projectiles

H. Khodarahmi, M. Zolfaghari, M. Foroutan Page 27

Many analytical models have been already presented for penetration analysis of long rod projectiles. In most of these models, for a specific projectile, target and impact specifications, only unknown parameter (the depth of penetration) is computed. In this paper, the formulation of Alekseevskii-Tate analytical model has been modified to be able to evaluate and design the projectile specifications, for a desired penetration depth. Also by additional relations for kinetic energy and no buckling conditions of projectile, a new algorithm is presented. In this method, by solving the resulted equations, the projectile specifications, including impact velocity, initial length, diameter and mass, is determined for a known penetration depth into the target. Comparison of the results of these formulations with other experimental works and numerical solutions by AUTODYN shows good agreement. Finally, as an applicable example, terminal ballistic design of a rod projectile is done, and projectile specifications are presented.

Abstract View Paper Original: Persian
Experimental Development of Explosive Forming of Flanged Domes over Male Die

S. Borji Page 37

This work presents an experimental approach to the development of explosive forming of aluminum flanged domes on a male die. Firstly, weight of explosive charge and standoff distance from blank were determined experimentally and fixed for all the subsequent tests. Then it was proved that forming conditions of dome and flange were improved substantially by increasing diameter of the blank and supporting the edge of the blank over a profiled supporting ring. The distributions of the strains were studied in the course of the development. Flanged domes made from thinner blanks were more prone to compressive instability in the form of wrinkles and folds of flange. Successful forming of domes from thinner sheet was performed by introducing evenly distributed notches around the blank edge.

Abstract View Paper Original: Persian
Kinetic Study on the Synthesis of Dimethyl Amino Ethyl Azide (DMAZ) as a Liquid Fuel

S.Ghambari, S. Sobhani, I. Kohsari Page 45

Dimethyl amino ethyl azide (DMAZ) is a good replacement for conventional liquid fuels, specially unsymmetrical dimethyl hydrazine (UDMH), due to suitable physicochemical and performance characteristics and low toxicity in aerospace industry for launching satellites. Azidation of 2-chloro N,N-dimethyl amino ethyl hydrochloride and neutralization of intermediate are two steps in synthesis of the fuel. The aim of the paper is the kinetic study on the production reaction of DMAZ. The methods of excess and equimolar concentrations were used for the dependency of the reaction rate on reactants and temperature. The results showed that the reaction was first order with respect to reactants. Moreover the integral method confirmed the reaction rate equation. The rate determining step was extremely endothermic with activation energy of 90 kJ.

Abstract View Paper Original: Persian
Coating of HMX Particles by Styrene/Butyl Acrylate/Acrylic Acid Terpolymer and Investigation of Coating Effects on Physico-Mechanical Properties of HMX/HTPB Particulate Composites

I. Amiri Amraee, M. Mehraban Sang-Atash, Y. Bayat Page 51

In this research, Styrene/Butyl Acrylate/Acrylic Acid terpolymer was synthesized by emulsion polymerization. Controlling effective parameters such as monomer composition and chain transfer agent, terpolymers with different molecular weight, glass transition temperatures and mean particle size diameter were synthesized. Experimental results showed latex with high molecular weight has a mean particle size diameter from 100-200 nm. For latex with low molecular weight, mean particle size diameter was 1000-1500 nm. The morphology of coated HMX particle was characterized by SEM technique. Experimental results showed that latex with low glass transition temperature has a higher surface and homogenous coating with respect to high glass transition temperature. Tensile measurement of particulate composites based on coated and uncoated HMX with HTPB showed that coated HMX with latex with 100-200 nm mean particle size diameter and glass transition temperature of 37 C have better mechanical properties with respect to uncoated HMX/HTPP particulate composite.

Abstract View Paper Original: Persian

به جمع مشترکان مگیران بپیوندید!

فهرست مطالب

فصلنامه مواد پر انرژی
سال پنجم شماره 1 (پیاپی 9، بهار و تابستان 1389)

فصلنامه مواد پر انرژی

Journal of Energetic Materials

به جمع مشترکان مگیران بپیوندید!

فهرست مطالب

فصلنامه مواد پر انرژی سال پنجم شماره 1 (پیاپی 9، بهار و تابستان 1389)

فصلنامه مواد پر انرژی

Journal of Energetic Materials

فصلنامه مواد پر انرژی
سال پنجم شماره 1 (پیاپی 9، بهار و تابستان 1389)