• Title/Summary/Keyword: 가속시험

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Prediction for Slag Mass Accumulation in the Kick Motor (킥모터 슬래그 적층량 예측)

  • Jang, Je-Sun;Kim, Byung-Hun;Cho, In-Hyun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.13 no.4
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    • pp.1-8
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    • 2009
  • Accumulated slag mass was predicted to estimate accurate performance of kick motor (KM) system. The validation of numerical analysis was performed with mass flow rate measured at the 4th ground test of the KM. The study described here includes the internal flow field of KM at various time steps during burning. Slag mass accumulation was analyzed through the aluminum oxide particle paths to predict slag mass deposition. Numerical analysis to solve both flow field and droplet accumulation was performed with Fluent 6.3 program. Analysing the effects of the acceleration, starting position and diameters of the aluminum oxide particles, total slag mass accumulation was obtained.

Thermal Reliability Analysis of a Closed Type Motor in an Axial Fan for the Large Space Ventilation (대형공간환기용 축류팬에 사용되는 밀폐형 모터의 열신뢰성 분석)

  • Lee, Tae-Gu;Hur, Jin-Huek;Moon, Sun-Ae;Yoo, Ho-Seon;Moon, Seung-Jae;Lee, Jae-Heon
    • Proceedings of the SAREK Conference
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    • 2007.11a
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    • pp.494-499
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    • 2007
  • The thermal reliability of the closed-type BLDC motor for the high speed axial fans is analyzed by a numerical method in this dissertation. Since the module and the motor part are combined in a closed case, the heat generated from a rotor in the motor and the electronic components in the PCB module can not be effectively removed to the outside. Therefore the module will easily fail by high temperature. The accelerated-life testing was accomplished to formulate the life equation and numerical method is used to predict the inside temperature of the PCB module, which is one of the life equation parameter according to the environment. The experiment for measuring the surface heat flux of the electronic components is carried out to apply the boundary condition of numerical study. When the environment temperature of BLDC motor is 21, 35 and $50^{\circ}C$, the temperature in the PCB space is predicted as 73.4, 87.5 and $102.4^{\circ}C$. Then the life time with the temperature are calculated as 2,239, 863 and 328.

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A study on the accelerated life test method of hose assemblies by applying Knockdown stress (녹다운 스트레스에 의한 유압호스 조립체의 가속수명시험에 대한 연구)

  • Ko, Jae-Myoung;Lee, Yong-Bum;Han, Sung-Geon;Yoo, Young-Chul;Kim, Hyoung-Eui
    • Proceedings of the Korean Reliability Society Conference
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    • 2006.05a
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    • pp.93-100
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    • 2006
  • The failure of hydraulic hose assemblies is caused by the impulse pressure and repetitive motions of bending and stretching (flexing) used at high pressure pipe in the form of bursting Since it takes long time to observe the bursting for life analysis, we can reduce test time by the method of applying the Knockdown stress which is equivalent to 70% of initial bursting pressure on rubber hose assemblies with maintaining the failure mode equally In this study, after scale parameter, shape parameter, and acceleration factor by preforming the impulse pressure test until the hose bursts, and finally analyzed the accelerated life.

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HTPB Propellant Ageing Property and HFC Base Shelf-Life Evaluation Method (HTPB 추진제 노화 특성 및 HFC 기반 수명 평가 기법)

  • Cho, Wonho;Westerlund, M.;Ryoo, Baek-Neung;Jung, Gyoo-Dong;Yoo, Ji-Chang
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.148-153
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    • 2017
  • During natural ageing of HTPB propellant undergoes a series of slow physico-chemical degradation reactions. By using accelerated ageing conditions it is possible to simulate the material behaviour at different time-temperature conditions especially focused on the in-service conditions. Ageing behaviour of HTPB propellant were investigated using HFC(Micro-Heat Flow Calorimeter) is universal technique for measuring the rate of slow chemical and physical processes in long-term storage.

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High Frequency Signal Analysis of Fuel Pump for Liquid Rocket Engine under Cavitating Condition (캐비테이션 환경에서의 액체로켓엔진용 연료펌프의 고주파 신호 분석)

  • Kim, Dae-Jin;Kang, Byung Yun;Choi, Chang-Ho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.1099-1102
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    • 2017
  • High frequency signals are analyzed which are measured at the inlet / outlet pipeline and pump casing during cavitation tests of the fuel pump for the liquid rocket engine. RMS values of each data are shown according to the cavitation number and compared with those of the LOx pump tests and the impact of the cavitation instability is also explored. Analogies about the cavitation number are confirmed between high frequency data of both pumps. In addition, the cavitation instability is found in all the signals and has an affect on the outlet pressure pulsation of the fuel pump.

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Trends of Innovative Clinical Drug Development using AMS (Accelerator Mass Spectrometry) and $^{14}C$-micro Tracer (가속질량분석기(Accelerator mass spectrometry, AMS)와 극미량 $^{14}C$-동위원소를 이용한 혁신적 임상시험개발동향)

  • Cho, Kyung Hee;Lee, Hee Joo;Choie, Hyung Sik;Lee, Kyoung Ryul;Dueker, Stephen R.;Shin, Young G.
    • YAKHAK HOEJI
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    • v.57 no.6
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    • pp.412-419
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    • 2013
  • Drug discovery and development processes are time consuming and costly endeavors. It has been reported that on average it takes 10 to 15 years and costs more than $ 1billion to bring a molecule from discovery to market. Compounds fail for various reasons but one of the significant reasons that accounts for failures in clinical trials is poor prediction/understanding of pharmacokinetics and drug metabolism in human. In an effort to improve the number of compounds that exhibit optimal absorption, distribution, metabolism, elimination (ADME), and pharmacokinetic properties in human, drug metabolism, pharmacokinetic scientists have been continually developing new technologies and compound screening strategies. Over the last few years, accelerator mass spectrometry (AMS) and its applications to preclinical/clinical pharmacokinetics and ADME studies have significantly increased, particularly for new chemical/biological entities that are difficult to support with conventional radiolabel studies. In this review, the application of AMS for micro-dosing, micro-tracer absolute bioavailability, mass balance and metabolite profiling studies will be discussed.

Storage Life Evaluation of a Violet Smoke Hand Grenade(KM18) using Degradation Data (열화데이터를 이용한 자색 연막수류탄(KM18)의 저장수명 평가)

  • Chang, Il-Ho;Hong, Suk-Hwan;Jang, Hyun-Jeung;Son, Young-Kap
    • Journal of the Korea Institute of Military Science and Technology
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    • v.15 no.2
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    • pp.215-223
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    • 2012
  • A violet smoke hand grenade(KM18) is used to generate signals. The grenade is considered to fail when its smoke emission time is longer than the specified one so that its smoke concentration becomes lighter. Accelerated degradation test for the grenade was performed, and then failure in smoke emission time was reproduced from the test. Stress for the degradation test was selected as temperature/humidity from the pre-test results. Degraded data of emission time from the accelerated test were analyzed through applying a distibution-based degradation model. Then, Peck Model was applied to predict the storage life under field conditions. In addition, the predicted storage life was compared with that of ASRP(Ammunition Stockpile Reliability Program).

Storage Life Estimation of Next Infrared Flare Material (차기 적외선 섬광제 저장수명 예측)

  • Back, Seungjun;Son, Youngkap;Kim, Namjin;Kwon, Taesoo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.3
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    • pp.311-318
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    • 2016
  • This paper shows storage life estimation of next IR(infrared) flare material through accelerated degradation tests. Three temperature conditions for the accelerated degradation tests are 55, 65 and $75^{\circ}C$. Six performances of IR flare material are burning time, IR peak/continuous Intensity, total energy of near/mid-IR and color ratio, and they were measured after the tests. Storage life of the IR flare material was estimated through both analyzing the degradation data of those performances and applying distribution-based degradation models to the data. Over 30 years of storage life at $20^{\circ}C$ is estimated in terms of IR peak intensity with reliability 0.99 and confidence level 99 %. Additionally, 10 years of storage period at $21^{\circ}C$ would be equivalent to 68 days of accelerated test at $65^{\circ}C$ from the activation energy in Arrhenius model.

Implementation of Data Monitoring and Acquisition System for Real-time Rotating Machinery based on oneM2M (oneM2M 표준 기반 실시간 회전기기 센싱 데이터 수집 및 모니터링 시스템 구현)

  • Lee, Young-Dong
    • Journal of the Institute of Convergence Signal Processing
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    • v.20 no.1
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    • pp.57-62
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    • 2019
  • In this paper, oneM2M based data monitoring and acquisition system is designed and implemented to measure and transmit the voltage, current, temperature, acceleration and vibration of the motor. The proposed system can detect electrical faults (overcurrent, reverse phase, phase loss, ground fault) and mechanical faults (MC counter, motor operation time, bearing and winding temperature, motor speed, insulation resistance). The system consists of sensor data collection, web server, php, database, wired/wireless communication system. The insulation resistance and the motor speed were measured, and the experimental results were similar for both the test resistance value and the reference input value.

Mechanical Properties of Diglycidy1 Ether of Bisphenol A/4, 4'-Methylene Dianiline/Malononitrile/Hydroquinone system (Diglycidy1 Ether of Bisphenol A/4, 4'-Methylene Dianiline/Malononitrile/Hydroquinone계의 기계적 특성)

  • Jeong, Seon-Gyeong;Lee, Jae-Yeong;Choe, Hyeong-Gi;Sim, Mi-Ja;Kim, Sang-Uk
    • Korean Journal of Materials Research
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    • v.4 no.7
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    • pp.823-827
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    • 1994
  • The mechanical properties of diglycidyl ether of bisphenol A(DGEBA)/4,4- methylene dianiline(MDA) system with the addition of malononitrile(MN) and hydroquinone(HQ) were investigated. The specimens which were prepared by curing at $150^{\circ}C$ for lhr after curing at $80^{\circ}C$ for 1.5hr were tested. The effects of MN as a chain extender and HQ, a reaction accelerator on the mechanical properties were investigated. With the increase of MN and HQ contents, impact property improved significantly but tensile property decreased.

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