• Title/Summary/Keyword: Cumulative Damage Rules

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Comparison of Cumulative Damage Models by predicting Fatigue lives of Aircraft Flaperon Joint (손상누적모델의 비교를 통한 플래퍼론 연결부의 피로수명 예측)

  • Park, Tae-Young;Park, Jung-Sun
    • Journal of Aerospace System Engineering
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    • v.3 no.4
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    • pp.27-34
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    • 2009
  • This paper deals with the lifetime prediction of Aircraft Flaperon Joint made of AISI 4130 steel. Reviews are performed on the published damage models at first. And three different damage models are used for predicting the fatigue life of the structure subjected to variable amplitude fatigue loading. These models require no increase in complexity of use, nor do they require additional material property or mission loading information to achieve the improved accuracy. Finally a comparison among the fatigue results is performed. It is observed that the Miner's rule could predict longer life than other cumulative damage models which take into account loads below the endurance limit.

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A Study on the Fatigue Strength of the Welds of Membrane Type LNG Tank (멤브레인 방식 LNG탱크 용접부의 피로강도에 관한 연구)

  • 김종호
    • Journal of Advanced Marine Engineering and Technology
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    • v.21 no.5
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    • pp.542-548
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    • 1997
  • In this study an evaluation method of fatigue strength of membrane type LNG tank is presented with FEM analysis and experimental approach of seam and raised edge welds. The study contains the following : l)FEM analysis of test specimens 2)Fatigue tests of seam and raised edge welds 3)Estimation of cumulative damage factor of the welds on the basis of safe life design concept complying with the rules of classification society 4)Review of the effect of mean stress on the fatigue strength 5)Modelling of fatigue life of the welds which is changeable by weld heights With the results obtained in this study, a model ${\Delta}{\delta}/h^2=0.13553\;{N_{f}}^{-0.3151}$ for seam and raised edge welds having a given weld height is proposed to be useful for designers and inspectors.

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Analysis on fatigue life distribution of composite materials (복합재료 피로 수명 분포에 관한 고찰)

  • 황운봉;한경섭
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.12 no.4
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    • pp.790-805
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    • 1988
  • Static strength and fatigue life scattering of glass fiber reinforced epoxy composite materials has been studied. Normal, lognormal, two-parameter and three-parameter Weibull distribution functions are used for strength and one-stress fatigue life distribution. The value of mean fatigue life is analysed using mean fatigue life, mean log fatigue life and expected value of 2 and 3-parameter Weibull distribution functions. Modification on non-statistical cumulative damage models is made in order to interpret the result of two-stress level fatigue life scattering. The comparison results show that 3-parameter Weibull distribution has better predictions in static strength and one-stress level fatigue life distributions. However, no advantage of 3-parameter Weibll distribution is found over 2-parameter Weibull distribution in two-stress level fatigue life predictions. It is found that two-stress level fatigue life prediction by the expanded equal rank assumption is close to the experimental data.

A Study on the Fatigue Strength of Highly Skewed Propeller (하이 스큐드 프로펠러의 피로강도에 관한 연구)

  • Kang Nak-Hwoun;Kim Jong-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.7
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    • pp.1131-1137
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    • 2004
  • Recently there has been a remarkable increase in the number of high speed and large ships and the high power involved for propulsion of above ships has brought high pitch ratio and highly skewed propeller. The recent tendency toward highly skewed propeller has increased the load on propeller blades, and the fatigue strength of propeller blades has become the critical point in design of propellers for ships. In this paper the effect of stress ratio and skew angle on the fatigue strength of highly skewed propeller, the statistical inference on the total revolutions of highly skewed propeller for 20 years under normal sea going state. and so on have been discussed. On the basis of above discussions, the highly skewed propeller blade thicknesses by the rules of classification society and the standards of manufacturer in country were compared and reviewed.

The International Arbitration System for the Settlement of Investor-State Disputes in the FTA (FTA(자유무역협정)에서 투자자 대 국가간 분쟁해결을 위한 국제중재제도)

  • Lee, Kang-Bin
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.38
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    • pp.181-226
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    • 2008
  • The purpose of this paper is to describe the settling procedures of the investor-state disputes in the FTA Investment Chapter, and to research on the international arbitration system for the settlement of the investor-state disputes under the ICSID Convention and UNCITRAL Arbitration Rules. The UNCTAD reports that the cumulative number of arbitration cases for the investor-state dispute settlement is 290 cases by March 2008. 182 cases of them have been brought before the ICSID, and 80 cases of them have been submitted under the UNCITRAL Arbitration Rules. The ICSID reports that the cumulative 263 cases of investor-state dispute settlement have been brought before the ICSID by March 2008. 136 cases of them have been concluded, but 127 cases of them have been pending up to now. The Chapter 11 Section B of the Korea-U.S. FTA provides for the Investor_State Dispute Settlement. Under the provisions of Section B, the claimant may submit to arbitration a claim that the respondent has breached and obligation under Section A, an investment authorization or an investment agreement and that the claimant has incurred loss or damage by reason of that breach. Provided that six months have elapsed since the events giving rise to the claim, a claimant may submit a claim referred to under the ICSID Convention and the ICSID Rules of Procedure for Arbitration Proceedings; under the ICSID Additional Facility Rules; or under the UNCITRAL Arbitration Rules. The ICSID Convention provides for the jurisdiction of the ICSID(Chapter 2), arbitration(Chapter 3), and replacement and disqualification of arbitrators(Chapter 5) as follows. The jurisdiction of the ICSID shall extend to any legal dispute arising directly out of an investment, between a Contracting State and a national of another Contracting State, which the parties to the dispute consent in writing to submit to the ICSID. Any Contracting State or any national of a Contracting State wishing to institute arbitration proceedings shall address a request to that effect in writing to the Secretary General who shall send a copy of the request to the other party. The tribunal shall consist of a sole arbitrator or any uneven number of arbitrators appointed as the parties shall agree. The tribunal shall be the judge of its own competence. The tribunal shall decide a dispute in accordance with such rules of law as may be agreed by the parties. Any arbitration proceeding shall be conducted in accordance with the provisions of the Convention Section 3 and in accordance with the Arbitration Rules in effect on the date on which the parties consented to arbitration. The award of the tribunal shall be in writing and shall be signed by members of the tribunal who voted for it. The award shall deal with every question submitted to the tribunal, and shall state the reason upon which it is based. Either party may request annulment of the award by an application in writing addressed to the Secretary General on one or more of the grounds under Article 52 of the ICSID Convention. The award shall be binding on the parties and shall not be subject to any appeal or to any other remedy except those provided for in this Convention. Each Contracting State shall recognize an award rendered pursuant to this convention as binding and enforce the pecuniary obligations imposed by that award within its territories as if it were a final judgment of a court in that State. In conclusion, there may be some issues on the international arbitration for the settlement of the investor-state disputes: for example, abuse of litigation, lack of an appeals process, and problem of transparency. Therefore, there have been active discussions to address such issues by the ICSID and UNCITRAL up to now.

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Consideration for IMO Type C Independent Tank Rule Scantling Process and Evaluation Methods (IMO C형 독립탱크의 설계치수 계산과정 및 평가방법에 대한 고찰)

  • Heo, Kwang-hyun;Kang, Won-sik;Park, Bong-qyun
    • Special Issue of the Society of Naval Architects of Korea
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    • 2017.10a
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    • pp.93-104
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    • 2017
  • IMO type C independent tank is one of the cargo containment system specified on IGC code. It is normally adopted for small and medium size liquefied gas carrier's cargo containment system and it can be applied to fuel tank of LNG fueled vessel. This study focuses on rule scantling process and evaluation methods in early design stage of type C independent tank. Actual design results of 22K LPG/Ammonia/VCM carrier's No.2 cargo tank are demonstrated. This paper presents the calculation methods of design acceleration and liquid height for internal design pressure as defined on IGC code. And this paper shows the applied results of classification rules about shell thickness requirement and buckling strength. Additionally this paper deals with evaluation methods of structural strength and cumulative fatigue damage using FE analysis.

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Fatigue Assessment of Reactor Vessel Outlet Nozzle Weld Considering the LBZ and Welding Residual Stress Effect (국부 취화부와 용접 잔류응력 효과를 고려한 원자로 출구노즐 용접부의 피로강도 평가)

  • Lee, Se-Hwan
    • Journal of Welding and Joining
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    • v.24 no.2
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    • pp.48-56
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    • 2006
  • The fatigue strength of the welds is affected by such factors as the weld geometry, microstructures, tensile properties and residual stresses caused by fabrication. It is very important to evaluate the structural integrity of the welds in nuclear power plant because the weldment undergoes the most of damage and failure mechanisms. In this study, the fatigue assessments for a reactor vessel outlet nozzle with the weldment to the piping system are performed considering the welding residual stresses as well as the effect of local brittle zone in the vicinity of the weld fusion line. The analytical approaches employed are the microstructure and mechanical properties prediction by semi-analytical method, the thermal and stress analysis including the welding residual stress analysis by finite element method, the fatigue life assessment by following the ASME Code rules. The calculated results of cumulative usage factors(CUF) are compared for cases of the elastic and elasto-plastic analysis, and with or without residual stress and local brittle zone effects, respectively. Finally, the fatigue life of reactor vessel outlet nozzle weld is slightly affected by the local brittle zone and welding residual stresses.