열 하중 기반의 리츠벡터와 순차적 센서위치 선택방법을 이용한 강건하고 효율적인 열 오차 모델링

현재엽(Jaeyub Hyun),유동윤(Dongyoon Yoo),이선규(Sun-Kyu Lee),왕세명(Semyung Wang) 대한기계학회 2011 대한기계학회 춘추학술대회 Vol.2011 No.10

Thermal deformations are among the most significant factors to errors generation of machine tool, this degrades the performance and accuracy of the machine tool. There are many methods to reduce the thermal deformation, such as structural designs to minimize thermal deformation, approaches to block and/or suppress thermal source, and thermal error compensation techniques to estimate and control thermal deformation. Among these, thermal error compensation techniques have been realized as the most successful method and actively studied. Securing of robustness and effectiveness of the thermal error modeling is directly correlated to the better compensation results. Most of the current thermal error modeling methods is highly dependent on measured data, and cannot consider mechanisms of the thermal deformation due to the thermal-structural interaction effect. In this paper, therefore, a novel and innovative strategy that can select the optimized thermal sensor placement and thermal error modeling method are proposed based on thermal load dependent ritz vectors. Operation state of the actual machine tool and thermal source variation are continuously changing according to the time. Thus, the various boundary conditions are applied to properly deal with these variations. The Wilson’s Ritz algorithm is used for generating the thermal load dependent Ritz vectors. Finally, for various 2D and 3D systems such as heat pipe and spindle, both existing thermal errors modeling method to use the eigenvectors and proposed method to use thermal load dependent ritz vectors are compared and investigated. Through this, the robustness and effectiveness are verified.

수치해석을 이용한 판넬과 스트립 및 유닛 레벨 반도체 패키지용 PCB의 열변형 해석

조승현,고영배 한국마이크로전자및패키징학회 2019 마이크로전자 및 패키징학회지 Vol.26 No.4

In this study, we conducted numerical analyses using the Taguchi method and finite element method to calculate the thermal deformation of a printed circuit board and the effect of design factors on the thermal deformation. Analysis results showed that the thermal deformation of the panel had the strongest effect on the thermal deformation and shape of the strip and unit. In particular, the deformation in the z direction was larger than that in the xy-plane direction. The effect of design factors and the design conditions for reducing the thermal deformation of the panel and strip changed at the unit level. Therefore, it is recommended that panel-level thermal deformation must be controlled to reduce the final thermal deformation at the unit level because the thermal deformation of the strip strongly affects that of the unit. 본 논문에서는 다구찌법과 유한요소법의 수치해석을 통해 인쇄회로기판의 열변형과 열변형에 미치는 설계인자의 영향도를 계산하였다. 인쇄회로기판의 패널과 스트립 레벨은 큐어링 온도조건에서, 유닛 레벨은 리플로우 온도조건에서 수치해석을 수행하였다. 해석결과에 따르면 패널의 열변형이 스트립과 유닛의 열변형량과 형상에 가장 큰 영향을미치며, 특히 z방향 변형량이 xy평면 방향의 변형량보다 크게 발생하였다. 열변형에 대한 설계인자의 영향도 분석 결과에 의하면 열변형을 줄이기 위한 설계인자들의 영향도와 설계조건이 패널, 스트립과 유닛 레벨에 따라 달라지기 때문에반도체 패키지의 신뢰성 향상을 목적으로 유닛 레벨의 열변형을 제어하기 위해서는 패널 레벨의 열변형을 제어할 필요가 있고 인쇄회로기판의 층별 두께는 설계인자 수준의 중간으로 선정하는 것이 필요하다.

FEM을 이용한 벤틸레이티드 디스크 브레이크 열응력 해석에 관한 연구

김성모(Sung Mo Kim) 한국생산제조학회 2009 한국생산제조학회지 Vol.18 No.5

Thermal brake judder caused by the high friction heat of the brake disk. Hot thermal judder makes serious problems such as to be unstability to drivers or to decrease braking force of automobile. Because thermal judder vibration makes high vibration occurrence and thermal deformation of brake disk. Therefore it is necessary to reduce or eleminate thermal judder phenomenon by understanding and investigation. This paper introduces the thermal deformation arising from friction heat generation in braking and proposes the FEM analysis to predict the distribution of temperature and thermal deformation. the results of the FEM analysis show the deformed shape and temperature distribution of the disk brake. The optimization is performed to minimize the thermal judder of ventilated disc brake that is induced by the thermal deformation of the disk brake.

Suppression of thermal deformation of machine tool spindle using TiC-Fe composite

Wonjun Bae,Junghwan Kim,Seungchan Cho,김양진,이상관 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.5

The minimization of error generation in machine tool spindle is important because high-speed and ultra-precision machining are extensively utilized in industrial fields. The thermal deformation of the machine tool spindle generated by the frictional heat between the outer and inner bearings can deteriorate the machining accuracy. In this study, a TiC-SUS431 composite was fabricated using the liquid pressing infiltration method to suppress thermal deformation, and its thermal properties were obtained by thermal characteristic tests. For the transient thermal analysis with finite element analysis, the parameters of the machine tool spindlebearing model were selected, and the boundary conditions were calculated. The temperature and thermal deformation of the analysis model were compared by applying SCM415 and TiCSUS431 to the material of the machine tool spindle and changing the rotation speed. From the analysis results, it was demonstrated that the TiC-SUS431 machine tool spindle can improve the machining accuracy by minimizing the spindle thermal deformation.

Sensitivity analysis of thermal deformation of CFRP laminate reflector due to fiber orientation error

Shun Tanaka,Tadashige Ikeda,Atsuhiko Senba 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.10

Carbon fiber reinforced plastic (CFRP) laminates are sometimes adopted as material of space observation systems because their specific stiffness is high and thermal deformation can be controlled by stacking sequence and fiber orientation. However, unexpected out-ofplane thermal deformation is generated on CFRP laminate plates because of fiber orientation error. In this research, a CFRP reflector model was built and its thermal deformation was measured to determine the kinds of deformation generated on the reflector. In the experiment, non-axisymmetric deformation was generated even for uniform heating. Finite-element analysis (FEA) on thermal deformation of the reflector model was performed to explain non-axisymmetric deformation. FEA showed that non-axisymmetric deformation was generated by fiber orientation error. The thermal deformation of the CFRP reflector model was strongly affected by fiber orientation error, and accordingly, the fiber orientation angle of CFRP reflectors should be controlled strictly depending on the desired accuracy.

IMC의 영향에 따른 Flip-Chip Bump Layer의 열변형 해석

이태경,김동민,전호인,허석환,정명영,Lee, Tae Kyoung,Kim, Dong Min,Jun, Ho In,Huh, Seok-Hwan,Jeong, Myung Young 한국마이크로전자및패키징학회 2012 마이크로전자 및 패키징학회지 Vol.19 No.3

최근 전자 제품의 소형화, 박형화 및 집적화에 따라 칩과 기판을 연결하는 범프의 미세화가 요구되고 있다. 그러나 범프의 미세화는 직경 감소와 UBM의 단면적 감소로 인하여 전류 밀도를 증가시켜 전기적 단락을 야기할 수 있다. 특히 범프에서 형성되는 금속간화합물과 KV의 형성은 전기적 및 기계적 특성에 큰 영향을 줄 수 있다. 따라서 본 논문에서는 유한요소해석을 이용하여 플립칩 범프의 열변형을 분석하였다. 우선 TCT의 온도조건을 통하여 플립칩 패키지의 열변형 특성을 분석한 결과, 범프의 열 변형이 시스템의 구동에 큰 영향을 미칠 수 있음을 확인하였다. 그리고 범프의 열변형 특성에 큰 영향을 미칠 것을 생각되는 IMC층의 두께와 범프의 직경을 변수로 선정하여 온도변화, 열응력 및 열변형에 대한 해석을 수행하였으며, 이를 통하여 IMC층이 범프에 영향을 미치는 원인에 대한 분석을 수행하였다. 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.

Machining Precision Improvement by Suppression of Spindle Thermal Deformation Using Metal-matrix Composite

W. Bae(배원준),Y. Kim(김양진) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월

Machining precision of the machine tool is affected by the performance of the machine tool spindle which is directly conducting a cutting process. The machine tool spindle is one of the biggest heat sources of machine tools, therefore, the generated heat can deteriorate the total machining process. In fact, thermally-induced errors account for 70% of the entire machining errors. In this study, a metal-matrix composite was used to suppress the thermal deformation of the machine tool spindle. Firstly, the TiC-SUS431 metal-matrix composite was produced by the liquid pressing infiltration method for acquiring the mechanical and thermal properties. After the parameters of the machine tool spindle model were decided, the boundary conditions were calculated for the transient thermal analysis. Finally, the values of the temperature and thermal deformation of the TiC-SUS431 applied spindle were obtained and compared with the values of the SCM415 which is the main material of the machine tool spindle. From the results, it was shown that the thermal deformation value of the metal-matrix composite applied machine tool spindle has been reduced by more than 35%. Therefore, the metal-matrix composite could be applied to the material of the machine tool spindle to suppress the thermal deformation.

디스크 브레이크에서 마찰열과 패드에 작용하는 융합 접촉거동에 관한 연구

한승철,이봉구 한국융합학회 2018 한국융합학회논문지 Vol.9 No.1

자동차 디스크 브레이크시스템에서는 열유속 및 열변형 등과 같은 이유로 마찰열이 균일하게 분산되지 않는다. 마찰열에 의한 열탄성 변형이 접촉압력 분포에 영향을 미치게 되고, 접촉하중이 디스크 브레이크 표면상의 작은 영역에 집중되어 열탄성 불안정성을 초래 할 수 있다. 본 연구에서는 실험적 계산식과 Kao 제안한 디스크와 패드의 접촉압력에 대한 해석방법을 참고로 하여 3차원 축대칭 모델을 통하여 실제로 제동 시 발생되는 디스크와 패드의 접촉을 고려한 온도 해석 및 열변형 해석을 하였다. ANSYS를 사용하여 디스크와 패드의 접촉면에서 발생하는 열탄성 불안전성 문제를 열하중과 기계적 하중으로 동시에 고려하여 해석하였다. 디스크와 패드가 직접 접촉하는 3차원 축대칭 모델을 구성하여 디스크의 마찰면 온도, 열변형, 접촉 열응력을 관찰함으로써 디스크에서 일어나는 열적 거동을 보다 정확하게 관찰하였다. In automotive disc brake systems, frictional heat is not uniformly dispersed for reasons such as heat flux and thermal deformation. The thermoelastic deformation due to the frictional heat affects the contact pressure distribution and the contact load may be concentrated on the contact portion on the the disc brake surface, resulting in thermoelastic instability. In this study, thermal analysis and thermal deformation analysis considering the contact between disk and pad occurred during braking through 3D axial symmetry model with reference to the experimental equation and Kao's analysis method of contact pressure of disk and pad. ANSYS is used to analyze the thermal and elastic instability problems occurring at the contact surface between the disk and the pad, considering both the thermal and mechanical loads. A 3D axisymmetric model with direct contact between the disk and the pad was constructed to more accurately observe the thermal behavior of the disk by observing the frictional surface temperature, thermal deformation and contact thermal stress of the disk.

Thermal-fluid-structure coupling analysis for plate-type fuel assembly under irradiation. Part-I numerical methodology

Li, Yuanming,Yuan, Pan,Ren, Quan-yao,Su, Guanghui,Yu, Hongxing,Wang, Haoyu,Zheng, Meiyin,Wu, Yingwei,Ding, Shurong Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.5

The plate-type fuel assembly adopted in nuclear research reactor suffers from complicated effect induced by non-uniform irradiation, which might affect its stress conditions, mechanical behavior and thermal-hydraulic performance. A reliable numerical method is of great importance to reveal the complex evolution of mechanical deformation, flow redistribution and temperature field for the plate-type fuel assembly under non-uniform irradiation. This paper is the first part of a two-part study developing the numerical methodology for the thermal-fluid-structure coupling behaviors of plate-type fuel assembly under irradiation. In this paper, the thermal-fluid-structure coupling methodology has been developed for plate-type fuel assembly under non-uniform irradiation condition by exchanging thermal-hydraulic and mechanical deformation parameters between Finite Element Model (FEM) software and Computational Fluid Dynamic (CFD) software with Mesh-based parallel Code Coupling Interface (MpCCI), which has been validated with experimental results. Based on the established methodology, the effects of non-uniform irradiation and fluid were discussed, which demonstrated that the maximum mechanical deformation with irradiation was dozens of times larger than that without irradiation and the hydraulic load on fuel plates due to differential pressure played a dominant role in the mechanical deformation.

소재변경에 따른 차량용 스크롤압축기의 열변형 해석

이형욱(Lee Hyoungwook),이근안(Lee Geunan),김정배(Kim Jeongbae) 한국태양에너지학회 2014 한국태양에너지학회 논문집 Vol.34 No.6

An inverter scroll compressor is used for the air conditioning in cars. Scrolls would be changed from the aluminum material to the magnesium material in order to satisfy the light weight trends of cars. The material changing influences on the scroll dimensions particularly the gap between two scrolls. Since the larger gap declines the performance of the compression, the gap between wraps of scrolls or the gap between wraps of scrolls to the plate of the opposite scroll is regarded as an important design variable. This paper is focused on the effects of the thermal stress due to the materials changing. The temperature difference between the inlet and the outlet is about 60 degrees and the highest operating temperature in the compressor is less than 110 degrees. The level of thermal stresses in the magnesium scroll is less than the result from aluminum one. The trend of the deformation is revealed that the normal directional deformation is 2 times lager than the in-plane directional deformation. Therefore the gap between the top of the wrap to the plate of the opposite scroll become more important than the other gaps. The orbiting scroll deforms larger than the fixed scroll by the thermal stresses. The deformation of the magnesium scroll is about 10% lager than that of the aluminum scroll. This value is similar to the ratio of the coefficients of thermal expansion of two materials. At the initial design stage, the results give many useful guides to engineers to propose gaps between parts.