• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.441-444
• /
• 2011

Type A and Type B and are commercial HTPB models, which are very popular prepolymer for polyurethane binder family. So the study has been performed on the physical, chemical characteristic of HTPB and viscosity, mechanical property of PBX-A applying to HTPB. But We excluded the Type A from Appication test, because of law Hydroxyl value. And in the case of Type B, Type B-1, 2 has mechanical disadvatage to apply to HTPB in the process comparing with B-3. It seems to make no problem if we change equivalence ratio or curing condition within standards. But if we are to apply process condition like R-45HT(US-sample), it would be essential to apply HTPB with higher Hydroxyl Value and hydroxyl Functionality.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1994.04a
• /
• pp.23-26
• /
• 1994

130mm D.B. 추진기관의 고온 시험에서 나타난 극심한 이상 연소 현상을 해결하기 위해 미세한 고체 입자들을 연소 가스에 분산시켜 불안정 연소를 억제하는 particulate damping 효과를 연구하였다. 고체 입자로서 효과적인 것으로 알려진 $K_2$$SO_4$. ZrC, Graphite를 CTPB, HTPB 고분자 물질에 충진시켜 epoxide, isocyanate 반응기와 가교 반응을 일으킴으로써 고무상의 탄성체 성질을 갖게 하는 $K_2$$SO_4$/CTPB, ZrC/Graphite/HTPB, ZrC/Graphite/AP/HTPB, ZrC/AP/HTPB 조성의 연소 안정제를 개발하였다. 이 연소 안정제는 외경 17mm, 길이 1000mm의 안정봉 형태로 제작하여 모타의 중심 cavity에 조립한 후 지상 연소 시험을 통하여 성능을 확인하였다. 시험 결과, 조성에 AP를 포함시켜 연소 안정제에 일정한 연소 속도를 부여하여 추진제 grain 연소 동안 고체 입자를 연소 가스에 분산되게 설계한 ZrC/Graphite/AP/HTPB, ZrC/AP/HTPB 조성의 연소 안정제가 불안정 연소 억제에 효과적인 것으로 나타났다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2009.11a
• /
• pp.207-210
• /
• 2009

The AP/HTPB composite propellant is a common choice for solid rocket propulsion. The externally heated rocket via fires, for instance, can cause the energetic substance to ignite, and this may lead to a thermal runaway event marked by a severe explosion. In order to develop preventive measures to reduce the possibility of such accidents in propulsion systems, we investigate the ignition and initiation properties of AP/HTPB propellant.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.20 no.1
• /
• pp.14-19
• /
• 2016

The viscosity and mechanical property of HTPB/AP composite solid propellant are profoundly affected by particle size of AP. In HTPB/AP propellant formulated by two mode of AP size such as $190{\mu}m$ and $7{\mu}m$, the propellant was found to be much less viscose at end of mix when coarse/fine AP ratio is ranged from 70/30 to 60/40 due to high solid packing fraction. It was shown that the toughness of tensile strength test for HTPB/AP propellant increased with the increase in coarse AP. Considering both lower viscosity and better tensile strength, the optimum ratio of AP coarse/fine was estimated to be 70/30.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.04a
• /
• pp.351-355
• /
• 2011

In this study, 2 kinds of HTPE insensitive propellants composed of HTPE/BuNENA binder, AP, AN and Al were investigated for combustion characteristics, ignition delay time, sensitivity and insensitive properties compared with HTPB propellant. HTPE propellant showed almost same sensitivity results as HTPB propellant, showed 2~3 times higher value than the value of HTPB propellant, ignition delay time respectively, and met the standard criteria, while HTPB propellant failed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.1
• /
• pp.9-14
• /
• 2019

Hydroxy-terminated polybutadiene (HTPB) propellants of solid rocket motors age differently under different storage temperatures. The shelf life of a solid rocket motor depends on the aging ratio of the HTPB propellant; it can be estimated through the viscoelastic properties by an aging test. This study analyzed the initial and natural aging properties during long-term storage. The initial properties were obtained from characterization and accelerated test results. The test results were obtained by analyzing the strain on cylindrical grains when a thermal load was applied.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.24 no.6
• /
• pp.101-107
• /
• 2020

In this paper, step-curing, which includes the change of curing temperature on the curing process, was applied to reduce curing day of HTPB/AP based propellant. This study targets the improvement of productivity of HTPB/AP based solid rocket motor. Comparison of mechanical properties of propellant resulted in the change of normal curing condition (60℃, 5 days) to step-curing condition (60℃, 1 day / 65℃, 3 days). Post-cure test was conducted to determine the impact on the shelf life of the solid rocket motor. The aging characteristics of propellants were analyzed by measuring mechanical properties and thermal expansion factor. To step-cured propellant, accelerated aging test was performed for 12 weeks, followed by tensile test. Sm(bar) and Em(%) were higher than 8 bar and 40% each, showing excellent mechanical properties.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.05a
• /
• pp.369-372
• /
• 2010

As analyzing friability of HTPE and HTPB propellants, the following results could be derived. The friability of the tested propellants depended on its binder contents, mechanical property, and burning rate. It was decreased as burning rate was lowered and toughness was increased.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• v.y2005m4
• /
• pp.75-78
• /
• 2005

The present work has been studied to investigate the effect of formulation on friability of HTPB/AP propellants including Butacene and $Cr_{2}O_3$. The mechanical properties and burning rate of the propellants were measured using Inston tensile tester and strand burner, respectively. Friability was calculated by shot-gun and closed bomb test. The result showed that friability was higher, as the content of Butacene or AP $6{\mu}m$ in the propellant formulations was increased.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.9 no.2
• /
• pp.40-45
• /
• 2005

In the present work, the effect of formulation on friability of HTPB/AP propellants including Betacene and $Cr_2O_3$ has been studied. The mechanical properties and burning rate of the propellants were measured using Inston tensile tester and strand burner, respectively. Friability was calculated from shot-gun and closed bomb test data. The result showed that friability was higher, as the content of Butacene or AP $6{\mu}m$ in the propellant formulations was increased.