• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.27 no.6
• /
• pp.625-633
• /
• 2014

Mark III CCS plate is considered in this paper to perform its strength assessment. Mark III CCS plate is designed and constructed by stacking various non-metallic engineering materials such as plywood, triplex and reinforced PU foam that are supported by series of mastic upon inner steel hull structure. From the viewpoint of structural analysis, this plated structure is treated as a laminated anisotropic structure. Commercially available general purpose finite element analysis programs such as MSC PATRAN and MARC are used to develop the finite element (FE) model of the Mark III CCS plate. Because of the characteristics of LNG cargo that the Mark III CCS plate deals with, it is subjected to a wide range of temperature variations, i.e. about $-163^{\circ}C$ to $20^{\circ}C$. Different material properties of the Mark III CCS plate at these temperature levels are considered in the FE model. Using the developed FE model, strength assessment procedure is developed incorporating various anisotropic failure criteria such as Hashin, Hill, Hoffman, Maximum stress and Tsai-Wu. The strength assessment is performed within the initial failure state of the Mark III CCS plate and, as a result, failure details such as failure locations and loads are identified.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.31 no.4
• /
• pp.165-171
• /
• 2018

In this study, the shape of the flow control structure within a DVR was designed for heat dissipation of the CPU. The proposed design consists of three thin metal plates, which directly controls the air flow inside the DVR box and forces the air to pass through the CPU, thereby efficiently dissipating heat from the CPU. The shape of the structure was determined using parametric studies. To verify the design result, we carried out a three-dimensional time dependent numerical analysis using a commercial fluid dynamics analysis package FlowVision. As a result of experiments with a real DVR equipment, it is confirmed that the temperature of the CPU is significantly reduced compared to the initial model.

• Journal of Advanced Navigation Technology
• /
• v.23 no.5
• /
• pp.460-465
• /
• 2019

In this study, we aim to derive a solution from the structural analysis for electrical failure of single board computers for computing navigation information. By analyzing the characteristic factor, we identify that crack occur on the central processing unit board due to a certain structural problem, and that the physical effect by the crack make communication function be impossible to perform, which it causes booting error. In order to find the location of excessive stress causing the crack, structural analysis for the single board computer is done. From the structural analysis, the areas where stress concentration occurs are identified, and improvement methods changing the structures are developed. As a result, we shows that stresses are reduced entirely on the stress distribution for the improved structure. In addition, heat analysis shows that changing the structure to reduce stresses is not affect to the heat radiation, and the thermal resistance of the actual equipment is verified by measuring the temperature of the heat sink applied with the improved structure.

• Proceedings of the KIPE Conference
• /
• 2020.08a
• /
• pp.304-305
• /
• 2020

본 논문은 초소형 전기자동차용 Low voltage DC-DC Converter(LDC)의 고전력밀도화 기법을 제시한다. Sync-Buck 구조를 사용해 구조를 단순화하고, Planar 인덕터 적용, PCB와 방열 plate를 사용하여 PCB와 방열 기구물의 접촉면을 증대시킴으로써 전력밀도를 향상시킬 수 있음을 보인다. 500W(12V, 41.67A)급 시제품 제작 및 배터리 입력 조건인 58V~84V 영역에서 실험을 통해 제안한 기법의 타당성을 검증한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.28 no.10
• /
• pp.394-401
• /
• 2016

The configuration of an extruded-type cooling structure was optimized for the light-emitting diode (LED) streetlights that have recently replaced convectional metal halide streetlights for energy saving. Natural convection and radiative heat transfer over the cooling structure were simulated using a numerical model with experimental verification. An improved cooling structure type was suggested to overcome the previous performance degeneration, as confirmed by analyzing the thermal flow around the existing cooling structure. A parameter study of the cooling structure geometries was also conducted and, based on the numerical results, the configuration was optimized to reduce the weight of the cooling structure. Consequently, the mass of the cooling structure was reduced by 60%, while the thermal performance was improved by 10%.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.1
• /
• pp.43-48
• /
• 2010

The heat sink system for a main board in a network server computer is built on printed circuit board by an anchor structure, mounted by eutectic SnPb solder. The solder creeping is caused by a constant high temperature condition in the computer and it eventually makes fatal failures. The FE model is used to calculate the stress and predict the life of soldered anchor in the computer. In the model, Anand constitutive equation is employed to simulate creep characteristics of solder. The creep test is conducted to verify and calibrate the solder model. A special jig is designed to mitigate the flexure of printed circuit board and to get the creep deformation of solder only in the test. Test results are compared with analysis and calibration is conducted on Anand model's constants. Precise life prediction of soldered anchor in creep condition can be performed by this model.

• Proceedings of the KIEE Conference
• /
• 2015.07a
• /
• pp.1256-1256
• /
• 2015

방열판과 같이 전류나 전압원에 연결된 도체의 구조물은 유기된 전류에 의해 전파를 방사하게 된다. 이때의 전류 분포는 도체 구조물의 형상과 주파수에 따른 전류 분포를 갖게 되는데, 이는 모드의 특성 해석을 통하여 분석할 수 있다. 원치 않는 전파의 방사를 이 특성 모드 해석을 통하여 분석하고, 이를 통해서 효율적인 접지 위치를 선정 후 최적의 저항을 사용하여 원치 않는 전파의 방사가 최소가 되도록 한다.

• Journal of Advanced Navigation Technology
• /
• v.24 no.4
• /
• pp.261-266
• /
• 2020

When a KW-class power control unit is installed in an aircraft installation, a heat dissipation design for a large amount of heat generated during power conversion should be considered. Failure to provide adequate heat dissipation can lead to equipment malfunction and fire, which can be a fatal factor in aviation operations. This paper describes the heat dissipation design of a KW-class power control unit installed in aircraft installation. The design and manufacturing test were conducted through computerized analysis, and the analysis model was corrected by confirming the rapid heat generation phenomenon of the heating element due to high power control. After the model revision, the design was improved, and the high-temperature operation test of the US military standard MIL-STD-810G was performed to confirm the feasibility of the improved design.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2011.04a
• /
• pp.531-538
• /
• 2011

To ensure the structural integrity of membrane type LNG tank, the rational assessment of impact pressure and structural responses due to sloshing should be preceded. The sloshing impact pressures acting on the insulation system of LNG tank are typical irregular loads and the structural responses caused by them also very complex behaviors including fluid structure interaction. So it is not easy to estimate them accurately and huge time consuming process would be necessary. In this research, a simplified method to analyze the dynamic structural responses of LNG tank insulation system under pressure time histories obtained by sloshing model test or numerical analysis was proposed. This technique basically based on the concept of linear combination of the triangular response functions which are obtained by the transient response analysis under the unit triangular impact pressure acting on structures in time domain. The validity of suggested method was verified through the example calculations and applied to the structural analysis of real Mark III type insulation system using the sloshing impact pressure time histories obtained by model test.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.2
• /
• pp.157-164
• /
• 2012

The design strategy of the multi-functional structure is that the electrical components and the circuits are directly put on their supporting structural panel in which the radiation shields and the thermal control functions are integrated. Applying the multi-functional structure reduces the total mass and size of the space system and makes it possible to lower launch cost. In present study the performance of thermal radiation for six types of multi-functional structure are investigated by the numerical method. The effect of the rib configuration on heat transfer for the multi-functional-structure is not important alone but is meaningful considering with the structural stiffness, difficulty of manufacturing and mass increase. In heat spreading point of view, the thickness of the outer conductive layer is important rather than the rib configuration and the trade-off study with the mass and thickness is required for optimum design.