• Journal of Welding and Joining
• /
• 제7권2호
• /
• pp.25-34
• /
• 1989

The purpose of this work is to coat ZrO$_{2}$ - 8Y$_{2}$O$_{3}$ ceramic on the Al cast alloy(AC-8A) by using the plasma spray method. Two types of coatings which were composed of two and three layer coating were examined. Each coating powder was analyzed for shape and size distribution and X-ray diffraction pattern. For the coated layers, microstructural analysis and performance estimation which was composed of static thermal test, thermal cyclic test and thermal shock test were conducted.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
• /
• pp.22-26
• /
• 2002

The goal of this study is to replace the current forward 2-piece propeller shaft of 8 ton large truck made of steel with 1-piece composite propeller shaft. A low cost Glass/Epoxy composite propeller shafts were successfully developed, which satisfy requirements such as the capacity of static torque transfer, fatigue strength and bending natural frequency. Devising secure joining method of a composite tube and metal yoke was the most critical issue in successful development of a high torque composite propeller shaft. In this study, joining method using thermal interference fit was adopted for composite to metal joint. Optimum conditions of heating temperature and interference level of thermal interference fit were determined from thermal stress analysis using 3D finite element method. Static torsion test, fatigue test, RPM and balance test were performed to verify the design.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.1948-1952
• /
• 2007

Heat transfer augmentation based on the process intensification concept in heat exchangers and thermal reactors has received much attention in recent years, mainly due to energy efficiency and environmental considerations. The concept consists of the development of novel apparatuses and techniques that, compared to those commonly used today, are expected to bring dramatic improvements in manufacturing and processing, substantially decreasing equipment size, energy consumption, and ultimately resulting in cheaper, sustainable technologies. The objective of this paper was to investigate the heat transfer characteristics of tubular thermal reactor using static mixing technology. Glycerin and water were used as the test fluids and water was used as the heating source. The results for heat transfer rate were strongly influenced by tube geometry and flow conditions.

• 한국기계가공학회지
• /
• 제18권11호
• /
• pp.83-88
• /
• 2019

In this study, the high-temperature high-pressure vessel was successfully manufactured, which can be used to store pressurized air and to increase the temperature for the mix performance test of high-temperature high-pressure air with coolant (e.g., water). In this research, static structure analysis and transient thermal analysis were performed using the commercial software Midas NFX 2015 R1. Based on the results, the optimized pressure vessel design was carried out. As a result of the optimized design, the minimum stress and minimum weight were found at 120 mm of the vessel thickness, and the optimized pressure vessel was verified. Finally, through manufacture and performance test (e.g., the non-destructive inspection and hydraulic pressure test), the reliability and safety were validated for the designed pressure vessel.

• Elastomers and Composites
• /
• 제53권4호
• /
• pp.220-225
• /
• 2018

Resilient pads play a major role in reducing the impact of loads on a rail in a rail-fastening system, which is essentially used for a concrete track. Although a compression set test is commonly used to measure the durability of a resilient pad, the static spring constant is often observed to be different from the fatigue test. In this study, a modified compression set test method was proposed to monitor the variations in the compression set and static spring constant of a resilient pad with respect to temperature and time. In addition, the life of the resilient pad was predicted by performing an acceleration test based on the Arrhenius equation.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집A
• /
• pp.9-15
• /
• 2001

In the case of a crack propagation, a portion of the work of inelastic deformation near the crack tip is dissipated as heat. In order to understand the thermal effect on fracture toughness, tensile test was carried out using thermocouples to monitor the variation of temperature with SA516 Gr70. The experimental results show that the temperature of specimen was increased $3.6^{\circ}C$ at static load condition. And the thermal effect was investigated connected with the steady-state stress in the vicinity of a crack propagation in the elastic-plastic C-T specimen theoretically. And fracture toughness, the energy to make crack surfaces, presented correctively. The fracture toughness with considering heat at the blunting of the crack tip ws lower about 19.3% than that of ignoring heat. So, it is resonable to apply the fracture toughness with considering thermal energy and it would be good explanation for constraint effect depending on the configuration in the presence of excessive plasticity.

• 항공우주기술
• /
• 제8권1호
• /
• pp.73-81
• /
• 2009

75톤급 터보펌프 개발을 위해 터보펌프 실 부위를 모사한 시험기를 제작하여 3종의 스태틱 실에 대한 상온 및 극저온 환경 기밀시험을 실시하였다. Conical 스태틱 실, PTFE 스태틱 실, C 스태틱 실을 적용한 기밀시험 결과 상온에서 기밀이 유지되더라도 산화제펌프의 이종 소재 사용에 따른 열수축률의 차이로 인해 PTFE 스태틱 실과 C 스태틱 실에서만 극저온 기밀이 유지되었고 Conical 스태틱 실에서는 극저온 기밀 유지에 실패하였다. 이는 기밀 면이 축방향인 PTFE 스태틱 실, C 스태틱 실과는 달리 Conical 스태틱 실의 기밀 면이 반경방향이므로 케이징의 반경방향 수축 시 기밀 면에 틈새가 생기기 때문인 것으로 파악된다. 더욱이 C 스태틱 실은 시험기 분해 후 재사용하여도 극저온 기밀이 유지되는 우수한 특성을 보였다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제13권4호통권56호
• /
• pp.159-169
• /
• 2009

본 연구는 다단계 온도프리스트레싱 공법으로 보강된 합성보의 하중재하 실험 및 구조해석을 통하여 온도프리스트레싱 공법의 프리스트레스 도입효과와 단면증가효과를 평가하였다. 연구결과 온도프리스트레싱을 이용한 합성보의 보강공법은 온도프리스트레싱에 의한 프리스트레스 도입 뿐 아니라 커버플레이트의 설치에 의한 단면증가로 합성보의 처짐 또한 감소시킬 수 있으므로 합성보의 효율적인 보강공법으로 적용이 가능할 것이다.

• Advances in aircraft and spacecraft science
• /
• 제7권3호
• /
• pp.251-269
• /
• 2020

Euclid is an optical/near-infrared survey mission of the European Space Agency (ESA) to investigate the nature of dark energy, dark matter and gravity by observing the geometry of the Universe and the formation of structures over cosmological timescales. The Euclid spacecraft mechanical architecture comprises the Payload Module (PLM) and the Service Module (SVM) connected by an interface structure designed to maximize thermal and mechanical decoupling. This paper shortly illustrates the mechanical system of the spacecraft and the mechanical verification philosophy which is based on the Structural and Thermal Model (STM), built at flight standard for structure and thermal qualification and the Proto Flight Model (PFM), used to complete the qualification programme. It will be submitted to a proto-flight test approach and it will be suitable for launch and flight operations. Within the overall verification approach crucial mechanical tests have been successfully performed (2018) on the SVM platform and on the sunshield (SSH) subsystem: the SVM platform static test, the SSH structure modal survey test and the SSH sine vibration qualification test. The paper reports the objectives and the main results of these tests.

• 폴리머
• /
• 제39권1호
• /
• pp.1-5
• /
• 2015

The effects of zeolite on the thermal stability of poly(vinyl chloride) (PVC) were investigated by the static thermal stability test, pyrolysis experiment and ultraviolet spectrum. The results showed that the porous zeolite could absorb hydrogen chloride (HCl), which suppressed the catalysis of HCl on thermal degradation of PVC, thus improved the thermal stability of PVC. The oxidizing acid which was loaded on zeolite had oxidated on the double bond that formed during the dehydrochlorination of PVC. This process could prohibit the growth of the conjugated polyene and improved the color of PVC. Hence, zeolite might be possible to come up with a high performance thermal stabilizer.