• 제목/요약/키워드: Fatigue Curve

검색결과 476건 처리시간 0.022초

이방성 전도 필름을 이용한 플립칩 패키지의 열피로 수명 예측 및 강건 설계 (Robust Design and Thermal Fatigue Life Prediction of Anisotropic Conductive Film Flip Chip Package)

  • 남현욱
    • 대한기계학회논문집A
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    • 제28권9호
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    • pp.1408-1414
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    • 2004
  • The use of flip-chip technology has many advantages over other approaches for high-density electronic packaging. ACF (anisotropic conductive film) is one of the major flip-chip technologies, which has short chip-to-chip interconnection length, high productivity, and miniaturization of package. In this study, thermal fatigue lift of ACF bonding flip-chip package has been predicted. Elastic and thermal properties of ACF were measured by using DMA and TMA. Temperature dependent nonlinear hi-thermal analysis was conducted and the result was compared with Moire interferometer experiment. Calculated displacement field was well matched with experimental result. Thermal fatigue analysis was also conducted. The maximum shear strain occurs at the outmost located bump. Shear stress-strain curve was obtained to calculate fatigue life. Fatigue model for electronic adhesives was used to predict thermal fatigue life of ACF bonding flip-chip packaging. DOE (Design of Experiment) technique was used to find important design factors. The results show that PCB CTE (Coefficient of Thermal Expansion) and elastic modulus of ACF material are important material parameters. And as important design parameters, chip width, bump pitch and bump width were chose. 2$^{nd}$ DOE was conducted to obtain RSM equation far the choose 3 design parameter. The coefficient of determination ($R^2$) for the calculated RSM equation is 0.99934. Optimum design is conducted using the RSM equation. MMFD (Modified Method for feasible Direction) algorithm is used to optimum design. The optimum value for chip width, bump pitch and bump width were 7.87mm, 430$\mu$m, and 78$\mu$m, respectively. Approximately, 1400 cycles have been expected under optimum conditions. Reliability analysis was conducted to find out guideline for control range of design parameter. Sigma value was calculated with changing standard deviation of design variable. To acquire 6 sigma level thermal fatigue reliability, the Std. Deviation of design parameter should be controlled within 3% of average value.

피로하중을 받는 Fiberite 934/T300 복합재료로 만들어진 연소관의 미세균열 연구 (Microcracking of Motor Case with Fiberite 934/T300 Laminates under fatigue Loads)

  • 김형원;김성은
    • 한국추진공학회지
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    • 제1권1호
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    • pp.82-88
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    • 1997
  • 복합재료의 미세균열을 연구하는데 변분이론을 이용한 에너지 방출율 이론이 쓰여졌다. Fiberite 934/T300 복합재료로 만들어진 압력용기에 피로하중이 가해졌을때 기계적 성질이 어떻게 변하는가에 이 논문의 연구 목적이 있다. 수정된 Paris-Law를 이용하여 에너지 방출율과 미세균열 성장률에 대한 master-curve를 그리면 어떤 피로하중 하에서도 복합재료의 미세균열에 관한 성장율을 예측할 수 있다.

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교량 확폭시 RC 상판 접합부의 휨 피로파괴거동에 관한 실험적 연구 (An Experimental Study on the Flexural Fatigue Fracture Behavior of RC Slab of Widened Bridge)

  • 박영훈;전준창;조병완;장동일
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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    • pp.13-18
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    • 1994
  • Most widened bridges have been constructed by the joining-construction method that makes new and existing bridge structurally single structure. However, joing-construction method has several problems in design and construction viewpoint. Therefore, this study is conducted in order to investigate structural behavior of widened RC slab and traffic-induced vibration of existing bridge during placing and curing of new concrete by the prototype flexural fatigue test. From the results of this study, it is shown that stress-concentration and slip occur between concrete and reinforcing rod at joint section but the reduction of load carrying capacity and of fatigue strength is negligible according to the traffic-induced vibration as well as the difference of construction method. A reasonable construction method for the bridge widening which takes into account the effects of the traffic-induced vibration and S-N curve for the widened bridge are also proposed.

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복합조직강의 저 및 고사이클 피로특성에 관한 실험적 연구(I) - 저사이클 피로특성 - (An Empirrical Study on Low and High Cycle Fatigue Properties of Dual Phase Steel (I) -Low Cycle Fatigue Properties -)

  • 옹장우;성낙원
    • 대한기계학회논문집
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    • 제10권4호
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    • pp.477-486
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    • 1986
  • 본 연구에서는 SM20C를 모재로 하여 입경의 크기가 다른 3종의 복합조직강을 제작 동일한 분위기에서 저 및 고사이클 전영역에 걸쳐 피로특성을 검토하고져 한다. 제일보는 그 중 저사이클특성에 대한 보고이다. 일반적으로 저사이클 피로현상은 재 료가 탄소성 상태하에서 전위, 미소크랙, 보이드(void) 등의 인자가 복합적으로 작용 하여 발생함으로 변형률속도, 제어파형, 온도, 시험방법 및 분위기에 따라 많은 영향 을 받는다. 따라서 본 연구에서는 두가지 실험방법을 사용, 응력-변형율거동을 검토 복합조직강의 피로특성과 입경크기가 피로거동 및 강도에 미치는 영향을 비교 고찰하 였다.

FRP 바닥판의 섬유직각 방향에 대한 피로해석 (Fatigue Analysis for Fiber Right Angle Direction of FRP Deck)

  • 김두환
    • 한국안전학회지
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    • 제29권6호
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    • pp.81-86
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    • 2014
  • Composite materials have high specific stiffness, specific strength than existing concrete or steel materials. It has superior dynamic properties when utilizing advantages of material such as Non-corrosive, light weight, non-conducting and it has superior mold ability which can make variable shapes. Thus, in the construction, for using composite materials as construction materials, the study carried out static strength of fiber right angle direction and fatigue performance of FRP deck member. The study is going to deduct S-N curve by analyzing the results comparatively and estimate long-term durability. From now on, the study is going to provide interpretation of FRP member and basic data of design basis, furthermore providing foundation technique of composite materials' application of structural frame is the goal of this study.

단조 금형의 수명 평가에 관한 연구 (A Study on Life Estimation of a Forging Die)

  • 최창혁;김용조
    • 소성∙가공
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    • 제16권6호
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    • pp.479-487
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    • 2007
  • Die life is generally estimated taking failure life and wear amount into consideration. In this study, the forging die life was investigated considering both of these two factors. The fatigue life prediction for the die was performed using the stress-life method, i.e. Goodman's and Gerber's equations. The Archard's wear model was used in the wear life simulation. These die life prediction techniques were applied to the die used in the forging process of the socket ball joint of a transportation system. A rigid-plastic finite element analysis for the die forging process of the socket ball was carried out and also the elastic stress analysis for the die set was performed in order to get basic data for the die fatigue life prediction. The wear volume of the die was measured using a 3-dimensional measurement apparatus. The simulation results were relatively in good agreement with the experimental measurements.

A Simplified Fatigue-Damage Model for the Comparison of the Randomness in Load and Strength

  • Oh, Chung Hwan;Oh, Hyung SooI
    • 품질경영학회지
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    • 제20권2호
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    • pp.21-32
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    • 1992
  • The only property of the random stresses to affect the life length are their damage amount and are independent of the especial realization in stress case. This paper shows the result is discussed that the randomness of the life length is caused by the randomness of the strength rather than by the randomness of the stress when the load is a random function and the strength is random as well. This special model is well-suited model for comparative calculations since it connects fatigue life for random stresses to fatigue life for periodically curve loads, which is usually measured in experiments.

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Surface Damage Accumulation in Alumina under the Repeated Normal-Tangential Contact Forces

  • Lee, Kwon-Yong;Choi, Sung-Jong;Youn, Ja-Woong
    • KSTLE International Journal
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    • 제1권1호
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    • pp.48-51
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    • 2000
  • Surface damage accumulation of alumina ceramics under the cyclic stress state was analyzed. The alternating stress state in repeat pass sliding contact was simulated by a synchronized biaxial (normal and tangential) repeated indentation technique. Wear debris formation mechanism through damage accumulation and fatigue grain failure in both alumina ceramic balls and flat disks was confirmed, and the contact induced surface degradation due to fatigue cracking accumulation was quantified by measuring vertical contact displacement. Variation of structural compliance (slope of load-displacement curve) of two contacting bodies was expressed as a variation of the apparent elastic property, called pseudo-elastic constant, of the contact system.

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해양구조물의 K-Joint 피로연구 (Fatigue Study of K-Joints for Offshore Structures)

  • 임성우;박노식;조철희;박관규
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2004년도 학술대회지
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    • pp.291-296
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    • 2004
  • The paper describes a test program on welded K-joints fabricated from circular hollow section brace members and chords made with API 2W 50 grade steel produced by POSCO. The K-joints were tested for three loading conditions at RIST. The specimens were tested in reaction frame that allowed vertical uniform loading to the structure. From the test, the crack initiation and development were observed and the fatigue failure could be predicted. The results were also compared with the provided S-N curves by DnV.

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강철도교 피로평가 시스템 개발 및 검증 (Test and Development of Fatigue Assesement System for Steel Railway Bridges)

  • 경갑수;최일윤;이준석;김이현;박진우
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2005년도 추계학술대회 논문집
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    • pp.185-190
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    • 2005
  • In order to evaluate that factors such as span length, member type and train loading affected on fatigue of steel railway bridges, in this paper, a series of field tests were carried out for some plate girder bridges. From the result estimated by rainflow counting method to analyze real strain-time curve obtained from the field test, it was known that the fatigue effect is more significant in the bridges having short span length and the secondary members regardless of train load types.

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