• 한국기계가공학회지
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• 제8권4호
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• pp.34-40
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• 2009

The effect of frictional factors on thermal stress and deformation volume of motorcycle brake disk was studied by using a disk-on-pad type friction tester. It has an effect on the frictional factor such as applied load, sliding speed, sliding distance and number of ventilated disk hole. However, it is difficult to know the mutual relation of these factors. In this study, thermal stress and deformation volume by using design of experiment with 4 elements were investigated for thermal analysis with regression analysis. Thermal stress and thermal deformation are obtained by the application of temperature from mechanical test. From this study, the result showed that the motorcycle brake disk with ventilated hole 3 had the most excellent thermal stress and deformation volume. The regression equation had a trust rate of 95% for the prediction of thermal stress and deformation volume of motorcycle brake disk was composed.

• 한국공작기계학회논문집
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• 제14권6호
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• pp.45-51
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• 2005

Braking performance of a vehicle can be significantly affected by the temperature increment in the brake system. Therefore, the important problem in brake system is to reduce the thermal effect by friction heat. Recently, many studies have been performed and good results have been reported on the prediction of the brake disk temperature. However, the study on the pad, piston and brake fluid temperature is rarely found despite of its importance. In this study, the temperature distribution of the disc brake system is studied according to the material properties of brake piston. Vehicle deceleration, weight distribution by deceleration, disc-pad heat division and the cooling of brake components are considered in the analysis of heat transfer. Unsteady state temperature distributions are analyzed by using the finite element method and the numerical results are compared with the experimental data.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.976-981
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• 2006

In case of attaching thermoelectric module and heat source, the polymer pad is attached on the $Al_2O_3$ plate, which is cooling side of thermoelectric module, in order to enhance mechanical safety of the system. It is impossible to calculate the exact distribution of temperature and flow pattern of inner gap of thermoelectric module. Therefore CFD(Computational Fluid Dynamics) analysis was executed to determine the thermo-fluid phenomena and distribution by Fluent. As the result of these analysis, heat transfer was dominated by conduction and the difference of temperature was linear distribution according to the thickness of polymer sheet.

• 드라이브 ㆍ 컨트롤
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• 제15권3호
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• pp.43-48
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• 2018

The hydraulic control valve, used in the CPB (cold-pad-Batch) cold dyeing system, passes through a pressurized material that absorbs the dye. The hydraulic control of the hydraulic control panel shall be driven in a uniform and precisely controlled manner, as it interferes directly with the dyschromatism. In this study, an acceleration test model was employed to verify the durability of the hydraulic control of the hydraulic control panel, which was manufactured by the scenic model, and the pre-roll angle was analyzed before the performance of acceleration test. Based on the change in the amount of deformation of the padder roll the durability of the padder roll was analyzed along with verification of the durability of the skin and the rubber coating in contact with the fabric. Furthermore, the accelerated test method used for hydraulic controlled multi-cell padder rolls was verified.

• Journal of Welding and Joining
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• 제13권2호
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• pp.82-95
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• 1995

This paper discusses distribution of thermal stress, strain at near the joint and investigates the reliability of solder joints of electronic devices on a printed circuit board. As Electronic devices are composed of different materials, thermal stresses generate at near the interface, such as solder joints and interface between lC device and lead frame pad due to the differences of thermal expansion coefficients, As results of thermal stress, strain, micro crack often occurs thermal fatigue fracture at the interface of different materials, The initiation and propagation of micro crack depend on the environmental conditions, such as storage temperature and thermal cycling. Finally, this paper experimentally shows a way to suppress micro cracks by using Fe-Ni alloy clad lead frame, and investigates crack and thermal fatigue fracture of TSOP(Thin small outline package) type on printed circuit board.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.127-131
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• 2008

In the disk braking of the railway trains, kinetic energy of the vehicles is converted into thermal energy by friction between a brake disk and the pad materials. This can be cause of the iterative thermal shock and generates thermal cracks on the brake disk surface. In this study, we show the comparative thermal fatigue test procedures and thermal crack analysis process to evaluate the thermal fatigue characteristics of candidate materials designed for development of heat-resistant brake disk material. We carried out tests on the conventional brake disk materials used for Saemaul and Mugunghwa trains, then we comparatively analyzed the thermal crack initiation and propagation on the surface of a specimen. A thermal fatigue test procedure and a crack analysis process were suggested to evaluate the heat resistance of the developed materials at later studies.

• 한국자동차공학회논문집
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• 제22권5호
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• pp.44-49
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• 2014

As expansion and contraction of bike disk brake are happened continuously by temperature at repeated urgent braking. In this study, 3 kinds of model are designed according to configurations of holes and thermal durabilities on bike disk brake are investigated by comparing 3 models through temperature and thermal analyses. Maximum thermal stress happened at the disk contacted with pad and the connection part fixing disk rotor. Instead of initial state, the temperature is uniformly distributed at transient state. As the area of hole at disk rotor face becomes wider, thermal stress becomes lower at the initial state. On the other hand, in case the number of holes increases, thermal stress becomes lower at the elapsed time of 100 seconds. The thermal durability of bike disk brake can be improved by applying this study result with configurations of holes.

• Tribology and Lubricants
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• 제25권2호
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• pp.102-107
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• 2009

The thermal deformation volume of motorcycle break disk was studied using a disk-on-pad type friction tester. Thermal deformation volume of motorcycle break disk have an effect on the frictional factor such as applied load, sliding speed, sliding distance and number of ventilated disk hole. However, it is difficult to know the mutual relation of these factors on thermal deformation volume. In this study, the thermal deformation volume with ANSYS workbench are obtained by application of temperature from mechanical test. From this study, the result was shown that the motorcycle break disk with ventilated hole 3 have the most excellent thermal deformation characteristics. The regression equation with frictional factors which have a trust rate of 95% for prediction of thermal deformation volume of motorcycle break disk was composed.

• 한국염색가공학회지
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• 제29권3호
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• pp.155-161
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• 2017

In CPB(Cold-Pad-Batch) dyeing, the rubber of the padder roll is influenced by the heat, chemical and mechanical influences and thus aging of the padder roll rubber occurs. This study presents an accelerated thermal aging test of the CPB padder roll rubber with strong alkali conditions. Using Arrhenius formula of the various property values for the various aging temperatures($80^{\circ}C$, $90^{\circ}C$, $100^{\circ}C$) of the padder roll, the accelerated life predictions could be calculated. The threshold value of the property was set at different values. The hardness was set at the point where 5% degradation occurs based on the actual use conditions, and the tensile strength was set at the point where 50% degradation occurs based on the general life prediction standards. From the results of the different physical properties at differing temperatures, the Arrhenius plot could be obtained. Through the usage of the Arrhenius Equation, significant duration expectation could be predicted, and the chemical aging behavior of the CPB padder roll could be found at the arbitrary and actual temperatures.

• 마이크로전자및패키징학회지
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• 제29권3호
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• pp.25-29
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• 2022

최근 전자 패키징 기술의 중요성이 대두되며, 칩들을 평면 외 방향으로 쌓는 이종 집적 기술이 패키징 분야에 적용되고 있다. 이 중 2.5D 집적 기술은 실리콘 관통 전극를 포함한 인터포저를 이용하여 칩들을 적층하는 기술로, 이미 널리 사용되고 있다. 따라서 다양한 열공정을 거치고 기계적 하중을 받는 패키징 공정에서 이 인터포저의 기계적 신뢰성을 확보하는 것이 필요하다. 특히 여러 박막들이 증착되는 인터포저의 구조적 특징을 고려할 때, 소재들의 열팽창계수 차이에 기인하는 열응력은 신뢰성에 큰 영향을 끼칠 수 있다. 이에 본 논문에서는 실리콘 인터포저 위 와이어 본딩을 위한 금속 패드의 열응력에 대한 기계적 신뢰성을 평가하였다. 인터포저를 리플로우 온도로 가열 후 냉각 시 발생하는 금속 패드의 박리 현상을 관측하고, 그 메커니즘을 규명하였다. 또한 높은 냉각 속도와 시편 취급 중 발생하는 결함들이 박리 양상을 촉진시킴을 확인하였다.