• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.5 s.45
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• pp.1-10
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• 2005

This study proposes a fatigue reliability evaluation procedure for steel-composite high-speed railway bridge based on dynamic analysis and investigates the effectiveness of Tuned Mass Damper(TMD) in terms of the extension of fatigue life of the bridge. For the fatigue reliability evaluation, the limit state is determined using S-N curve and linear fatigue-damage accumulation. Dynamic analyses are peformed repeatedly to consider the uncertainties of train-velocity and damping ratio of the bridge. The distribution of random variables related to fatigue damage for the intended service life is then statistically estimated from analytical results. Finally, the fatigue reliability indices are obtained by means of the Advanced First-Order Second-Moment (AFOSM) method. Through numerical simulation of a steel-composite bridge of 40m span, the effectiveness of TMD on fatigue life of the bridge is examined and the results are presented.

• Journal of the KSME
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• v.43 no.6
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• pp.47-51
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• 2003

이 글에서는 전자 패키지 열적.기계적 신뢰성 평가 기술의 현황과, 전자 패키지의 신뢰성 설계를 위한 피로 실험, 미소 변형측정, 유한요소 해석을 통한 파손 해석 등의 관련 기술들을 소개한다.

• Proceedings of the Korean Reliability Society Conference
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• 2006.05a
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• pp.32-39
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• 2006

전자 부품의 신뢰성 평가를 위해서 다양한 방법의 시험법이 사용된다. 전자 부품은 반복적인 작동과 휴식에 의한 열피로를 받게 된다. 이에 대한 신뢰성 평가를 위해 오래전부터 다양한 시험 규격이 만들어지고, 그에 따라 열챔버를 이용한 챔버 사이클링 시험이 수행되고 있다. 하지만, 최근에는 이러한 시험 규격들에 대한 문제가 지적되고 있으며, 또한 챔버 사이클링을 이용한 가속 실험의 경우 실제 작동환경을 완벽히 묘사하지 못하며, 가속할 수 있는 정도가 제한되고 있다. 본 연구에서는 파워 사이클링 시험을 묘사하는 시험 방법을 제안하고, 그를 이용하여 BGA 패키지의 솔더 조인트에 대한 열피로 시험을 수행하였다. 본 연구에서 제안된 파워 사이클링 시험기는 실제 작동 환경과 유사한 온도 구배를 패키지에 만들어 준다. 그리고 패키지에 열전도를 이용하여 열을 공급함으로써, 대류를 통해 열을 공급하는 챔버 사이클링 시험에 비해 빠르게 가열 및 냉각이 가능하다. 파워사이클링 테스트 방법을 이용하여 다양한 온도 조건에 대해 열피로 수행하여 솔더 조인트의 열피로 특성을 평가하였다.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.1
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• pp.93-102
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• 1992

In this paper presented is the reliability analysis of a double skinned hull structure against the ultimate bending moment and fatigue strength under longitudinal bending. The ultimate bending strength is obtained through the beam-column approach in which the load-end shortening curves(stress-strain curves) of stiffened plates under mini-axial compression are derived using the concept of plastic hinge collapse. The fatigue damage only is considered as fatigue failure for which the Miner's damage rule is employed. Assessed are fatigue reliability for the possible joint types found at deck structure. Also included is the reliability analysis of a series system of which elements are ultimate and fatigue failure.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.2
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• pp.74-82
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• 1998

To evaluate the reliability against fatigue failure of offshore structures, a fatigue reliability analysis model based on the probabilistic approach has been developed. In this model, the simplified method is adopted as a fatigue analysis method. The uncertainties included in the fatigue analysis are considered as random variables and their statistical properties are evaluated as quantitatively as possible using existing data. As an example, the developed fatigue reliability model is applied to the jacket. And then the relative significance of each uncertainty on the probability of fatigue failure is surveyed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.12
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• pp.1048-1058
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• 2017

One of the failure mechanism of spaceborne electronics is a fatigue fracture on solder joint under launch random vibration. Thus, a necessity of early diagnosis through the fatigue life evaluation on solder joint arises to prevent such potential risk of failure. The conventional life prediction methods cannot assure the accuracy of life estimation results if the packaging type changes, and also requires much time and effort to construct the analysis model of highly integrated PCB with various packaging types. In this study, we performed life prediction of PCB based on a reliability and life prediction tool of sherlock as a new approach for evaluating the structural reliability on solder joint, and those prediction results were validated by fatigue tests. In addition, we also investigated an influence of solder height on the fatigue life of solder joint. These results indicated that the Sherlock is applicable tool for evaluating the structural reliability of spaceborne electronic.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.350-353
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• 2009

In the fatigue analysis and the components design, uncertainties are caused by the variances of geometry data and applied loads, and the scatter of material properties. In this paper, fatigue crack growth life of turbine is evaluated by fracture mechanics and the reliability analysis is accessed by the fist order second moment method and Monte Carlo simulation.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.1
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• pp.189-196
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• 1991

This paper is an illustration of the application of the reliability analysis to the transverse structure of a SWATH ship. The ultimate strength of plate members on the cross structure and upper part of strut are considered in the reliability analysis. The fatigue reliability analysis has been also carried out at the junction of cross structure, sponsors and strut. Included is also an example of the allowable fatigue damage level. Demonstrated is the reliability study of series system of which elements are the ultimate and fatigue failure as well. Doing this would be desirable to get a truer solution of the structural safety level. The paper ends with a brief summary of the present reliability study and same important points which may be useful at the design stage.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.537-546
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• 2010

This research work contributed to a study for the procedure and methodology to assess the fatigue durability for a composite torque link of helicopter landing gear, which was newly developed and fabricated by the resin transfer moulding technique to interchange with metal component. The simulated load spectrum anticipated to be applied to the torque link during its operation life was generated using an advanced method of probabilistic random process, and the fatigue durability was evaluated by the strength degradation approach on the basis of material test data. The full scale fatigue test was also performed and compared with the analysis results.

• Journal of the KSME
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• v.43 no.6
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• pp.62-65
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• 2003

이 글에서는 가속 열노화시험을 통하여 노화수명을 예측하고 방법을 고무 재료의 수평 선도와 유한요소해석 결과로 부터 고무부품의 피로숙명을 예측하여 신뢰성을 평가하는 방법을 소개하였다.