• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.30 no.5
• /
• pp.208-213
• /
• 2020

In this research, design optimization was investigated using the finite element analysis and the optimal design technique based on the PQRSM algorithm to minimize the thermal deformation of IGZO oxide in a target module in which IGZO oxide and a copper backplate are bonded to each other. In order to apply the optimal design technique in conjunction with finite element analysis, the x-coordinate of lower supports and upper fixed boards used as design valuables, and the optimal design was performed to minimize the thermal displacement of IGZO materials as the objective function. After the optimization process, the thermal displacement within IGZO oxide could be reduced to 42 % comparing with the initial model. The result is thought to be useful in the industry as it can reduce the thermal deformation of target oxides materials only by changing the position of the subsidiary materials during the bonding process.

• Journal of the Microelectronics and Packaging Society
• /
• v.19 no.3
• /
• pp.49-56
• /
• 2012

Recently, by the trends of electronic package to be smaller, thinner and more integrative, fine bump is required. but It can result in the electrical short by reduced cross-section of UBM and diameter of bump. Especially, the formation of IMCs and KV can have a significant affects about electrical and mechanical properties. In this paper, we analyzed the thermal deformation of flip-chip bump by using FEM. Through Thermal Cycling Test (TCT) of flip-chip package, We analyzed the properties of the thermal deformation. and We confirmed that the thermal deformation of the bump can have a significant impact on the driving system. So we selected IMCs thickness and bump diameter as variable which is expected to have implications for characteristics of thermal deformation. and we performed analysis of temperature, thermal stress and thermal deformation. Then we investigated the cause of the IMC's effects.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.42 no.10
• /
• pp.809-815
• /
• 2014

The co-bonded dissimilar composite under a wide range of temperature change shows thermal distortion due to the differences in thermal expansion characteristics of the composite materials. Analysis of the thermal expansion characteristics of each composite is required for the design of co-bonded dissimilar composite structure with considering the shape distortion during the manufacturing process. In this work, digital image correlation (DIC) technique is introduced for measuring the thermal distortion characteristics of co-bonded dissimilar composite specimen, carbon/epoxy and silica/phenolic. The thermal distortion of co-bonded dissimilar composite specimen is numerically estimated and compared with the experiments. The estimated results is successfully validated using the measured results.

• Journal of the Microelectronics and Packaging Society
• /
• v.10 no.3
• /
• pp.73-82
• /
• 2003

Recently, PWB(Printed Wiring Board) has been recognized in the field of microelectronic package as core technology for designing or manufacturing. PWB is the structure stacked by several materials with different thermophysical properties, which shows the different CTEs(Coefficient or Thermal Expansions) during the fabrication process and causes a lot of defects such as warpage, shrinkage, dimension, etc. Thermal deformation of PWB is affected mainly by the volume change of solder-resist among fabrication parameters. Therefore, thermal deformation of PBGA and CSP consisting of 2 layers and 4 layers was studied with solder-resist process. When over 30% in volume fraction of solder-resist, thermal deformation of 2-layered PWB was min. 40% higher than that of 4-layered PWB because 4-layered PWB contained the layer with high toughness such as prepreg, which counterbalanced the thermal deformation of solder-resist. Otherwise, when below 30%, PWB showed similar thermal deformation without regard to layers and design.

• The Journal of the Acoustical Society of Korea
• /
• v.38 no.3
• /
• pp.344-351
• /
• 2019

In this work, the mechanism of contraction and expansion noise generation is investigated, and effective methods are proposed to reduce the occurrence frequency of noise during operation of the refrigerator. First, the frequency spectrum analysis was made by using the sound pressure signal measured in an anechoic chamber to investigate the characteristic of noise and the frequency of occurrence. Second, a thermal deformation analysis was conducted to predict the location of noise source. It is found from the analysis that the biggest thermal deformation occurs in the middle of the left inner case in the freezer room. Following the investigation made, a noise reduction method is proposed. The method is proposed to reduce the contraction and expansion noise by reducing the thermal deformation through increasing ABS (Acrylonitrile Butadiene Styrene) thickness in the center of refrigerator.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.04b
• /
• pp.215-219
• /
• 1995

요사이 공작기계는 고생산성을 위해 고속절삭과 강력 절삭이 가능하도록 설계되고, 고성능의 Controller를 부착하여 이송과 공구착탈에 필요한 비절삭 시간을 급격히 단축시켜 나가고 있다. 본 연구에서는 공작기계 주축 베어링의 비대칭 벌열의 원인과 발열형태를 이론적으로 예측하고, 실험에 의해 비대칭 발열과 냉각특성 을 운전조건 별로 확인하였다. 또한 비대칭 발열이 주축대의 열변형에 어떤 영향을 미치는지 알기 위해 유 한요소법에 의해 열변위 특성을 분석하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.1048-1050
• /
• 2017

In this study, Numerical simulations of the pintle-nozzle were performed to evaluate the thermal strain effect using by 1-way fluid structure interaction analysis(FSI). we carried out computational fluid dynamics analysis to obtain the pressure and temperature fields of pintle nozzle. we then used the data as the load condition for a FSI separately. and thermal strain of the pintle was checked. In order to confirm the change of thrust characteristic by deformation, we are carrying out 2-way FSI.

• 기계와재료
• /
• v.22 no.1
• /
• pp.54-64
• /
• 2010

공작기계의 고속화, 다축화, 복잡화에 따른 열변형 오차가 공작기계에서 발생하는 오차의 대부분을 차지하고 있다. 이러한 열변형 오차를 최소화 하기 위해 공작기계의 발열부에 차가운 오일을 공급하여 냉각함으로써, 열변형을 제거하는 장치가 오일쿨러이다. 오일쿨러는 제어 방법에 따라 On-off, 가스 바이패스, 인버터 방식 등이 사용된다. 초정밀 공작기계에는 주로 가스 바이패스 및 인버터 방식이 사용되는데, 인버터 방식의 경우 고가(高價)인 관계로 주로 옵션 형태로 사용된다. 가스 바이패스 방식 오일쿨러는 인버터 방식에 비해 가격이 저렴하고 구조가 간다하며 정밀한 온도제어를 할 수 있지만 부하가 낮은 경우 구조적인 한계로 인해 온도제어 불안정을 발생시킨다. 본 연구에서는 기존 바이패스 방식 오일쿨러에서 나타나는 문제점을 해결하고 보다 정밀한 온도제어를 위해 2개의 전자밸브를 갖는 듀얼 밸브 방식 오일쿨러 시스템을 개발하였다. 개발된 듀얼 밸브 오일쿨러 시스템의 성능검증을 위해 정격운전, DIN 8602 규격, ISO/DIS 230-3 운전모드에서 성능을 비교/분석하였다.

• Journal of Satellite, Information and Communications
• /
• v.5 no.1
• /
• pp.75-79
• /
• 2010

Satellite structure is distorted by thermal load in orbit. The structural distortion induces the pointing errors of observation unit that is difference between initial pointing direction at ground integration and at in-orbit. In that case, satellite is not able to point along required direction. As observation capability becomes higher, structural distortion due to thermal load should be smaller to achieve successful mission. In this paper, the method to predict pointing error and results are described.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.9
• /
• pp.126-132
• /
• 2016

This study numerically investigates the characteristics of chemical reactions and thermal deformation in a steam reformer. These phenomena are significantly affected by the high-temperature burner gas and the process gas conditions. Because the high temperature of the burner gas ranges from 800 to 1000 K, the reformer tubes undergo substantial thermal deformation, eventually resulting in structural failure. Thus, it is necessary to understand the characteristics of the reaction and thermal deformation under the operating conditions to evaluate the reformer tubes for sustainable, stable operation. Extensive numerical simulations were carried out using commercial CFD code (ANSYS FLUENT/MECHANICA Ver. 13.0) while considering three-dimensional turbulent flows and combined heat transfer including conduction, convection, and radiation. Structural analysis considering conjugated heat transfer between solid tubes and fluid flows was conducted using the Fluid-Solid Interaction (FSI) method. The results show that when the injection temperature of the process gas and burner gas decreased, the hydrogen production rate decreased significantly, and thermal deformation decreased by at least 15 to 20%.