Center for Energetic Concepts Development, Department of Mechanical Engineering, University of Maryland

Sympathetic Reactions

1. Factors Affecting Sympathetic Ignition of Three-impulse-at-one-spot Thruster
Guo Ning, Yan Nan and Wang Pei-lan, Chinese Journal of Energetic Materials, 2010, 18(1):51~54

Abstract: Three-impulse-at-one-spot thruster is a device which initiates three igniters by logic igniting circuit, and achieves trajectory correction for various flight vehicles. The effects of different main charge amounts, thickness of sealing film and combustion chamber volume on sympathetic ignition of the igniters were analyzed. Results show that output performance improves by increasing main charge amount while sympathetic ignition taking place after excessive charge, so 175-200 mg charge amount is suggested. The sympathetic ignition is effectively prevented by increasing thickness of sealing film while excessive thickness brings too much energy loss, so 0.3 mm thickness of sealing film is suggested. The sympathetic ignition is effectively prevented by increasing combustion chamber volume while too large volume will result in excessive whole dimension, so 3.7 mL chamber volume is suggested.

2. Attenuation Regularity of Detonation Wave of Small Charge in PMMA, XU Xin-chun, JIAO Qing-jie, CAO Xiong, HU Shuang-qi and ZHAO Hai-xia, Chinese Journal of Energetic Materials, 2009, 17(4):431~435

Abstract: The output shock wave pressure attenuated by different thicknesses of PMMA gaps of booster JO with small size charge diameter was measured by manganin piezoresistance method. The exponential regularity of the shock wave attenuation coefficient versus the charge diameter in PMMA was obtained by fitting experimental data. The load density of the booster was 90% of the theoretical density, and the charge diameter was 1.5 mm, 3 mm, 5 mm and 8 mm with confinement of 45# steel and PMMA. Results show that the attenuation coefficient tends to decrease with the increasing of the charge diameter under the same confinement. The confinement of the charge is stronger, the change is more obvious.

3. Damage of DMMP under Shockwave Pressure, HE Song-wei, HAN Yong, LI Hai-bo and MA Hua, Chinese Journal of Energetic Materials, 2009, 17(5):558~560

Abstract: Damage of dimethyl methyl phosphonate (DMMP) under shockwave pressure induced by explosive detonation was studied. The decomposition of DMMP sample impacted by shockwave was mensurated quantitatively by gas chromatography, and the sample component was analyzed by gas chromatography-mass spectrograph. Results show that the DMMP impacted by high pressure decomposes partly, and the DMMP content is reduced from 93.81% to 84.77% with increasing of the pressure in the range of 12.24-22.41 GPa.

4. Reaction Rule for Explosive under Different Shape Warhead Impact in Steven Test
DAI Xiao-gan, SHEN Chun-ying, WEN Yu-shi and XIANG Yong, Chinese Journal of Energetic Materials, 2009, 17(1):50~54.

Abstract: Steven test for PBX-2 explosive was made by using little blunt warhead, pin shape warhead and plane projectiles of 2.0 kg. The pressure change was measured by manganin pressure gauges and poly vinylidena fluoride(PVDF) piezofilm stress gauge. Ignition process was analyzed by high-speed motion pictures. The reaction overpressure of explosive was obtained by blast pressure gauges. Reaction for explosive was analyzed under different shape warhead impacts in Steven test. The results show that explosive reaction is more intensive because of strong shear band under plane impact in Steven test, and reaction degree for PBX-2 explosive is higher under plane warhead.