• 제목/요약/키워드: J-failure

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탄소성 파괴역학적 건전성 평가 시스템의 개발 I (A Development of Integrity Evaluation System Based on Elastic Plastic Fracture Mechanics(I) - Specimen Cases -)

  • 김영진;최재붕;손상환;이주진;허용학
    • 대한기계학회논문집
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    • 제14권3호
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    • pp.646-655
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    • 1990
  • 본 연구에서는 EPIES 프로그램의 상세한 내용과 이를 이용한 5가지 파괴역학 시편에 대한 사례 연구에 대하여 보고하고자 한다.

점 용접점 파단의 정량적 모델-1. 파단조건식 (An Estimative Model of Spot Weld Failure-1. Failure Criteria)

  • 이태수;이형일;신수정
    • 한국자동차공학회논문집
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    • 제6권6호
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    • pp.40-52
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    • 1998
  • A good grasp of the failure mechanisms of resistance spot weld, widely used in joining the auto-panels, in essential to the structural/crashworthy analyses and integrity assessment of the whole auto-body. In this study, We provide an estimative model describing the failure behavior of resistance spotf weld, and apply the model to the finite element analysis of crashworthiness. First, in "Part 1-Failure Criteria", to be used for the finite element analysis of spot-welded structural panels of an auto-body, (i) a methodology for quantifying the spot weld failure and the accompanying failure criteria are presented, and (ii) the coefficients of the failure equation are determined by a munimum number of appropriate experimental tests. To achieve these, we derive the functional form of the failure envelop by limit analysis, and correlate it with the form in PAM-$CRASH^{TM}$ code, and also investigate the effect of the failure coefficients on the failure envelop form. An estimative model obtained in this Part1, as spot weld failure criteria is applied to the Macroscopic finite element analysis of autobody structural panels using PAM-$CRASH^{TM}$ code in Part 2.

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Effects of interface angles on properties of rock-cemented coal gangue-fly ash backfill bi-materials

  • Yin, Da W.;Chen, Shao J.;Sun, Xi Z.;Jiang, Ning
    • Geomechanics and Engineering
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    • 제24권1호
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    • pp.81-89
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    • 2021
  • Uniaxial compression tests were conducted on sandstone-CGFB composite samples with different interface angles, and their strength, acoustic emission (AE), and failure characteristics were investigated. Three macro-failure patterns were identified: the splitting failure accompanied by local spalling failure in CGFB (Type-I), the mixed failure with small sliding failure along with the interface and Type-I failure (Type-II), and the sliding failure along with the interface (Type-III). With an increase of interface angle β measured horizontally, the macro-failure pattern changed from Type-I to Type-II, and then to Type-III, and the uniaxial compressive strength and elastic modulus generally decreased. Due to the small sliding failure along with the interface in the composite sample with β of 45°, AE events underwent fluctuations in peak values at the later post-peak failure stage. The composite samples with β of 60° occurred Type-III failure before the completion of initial compaction stage, and the post-peak stress-time curve initially exhibited a slow decrease, followed by a steep linear drop with peaks in AE events.

저온환경에서 복합재료 핀 연결부의 Bearing 강도에 관한 연구 (A Study of Bearing Strength on Composite Pinned-Joint at Low Temperature)

  • 허남일;이상연;김재훈;이영신;사정우;조승연;임기학;오영국;최창호;도철진;권면;이경수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집A
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    • pp.413-418
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    • 2001
  • Fundamental failure mode in a laminated composite pinned-joint is proposed to assess damage resulting from stress concentration in the plate. The joint area is a region with stress concentrations thus a complicated stress state exists. The modeling of damage in a laminated composite pinned-joint presents many difficulties because of the complexity of the failure process. In order to model progressive from initial to final, finite element methods are used rather than closed form stress analyses. Failure analysis must be a logical combination of suitable failure criteria and appropriate material properties degradation rules. In this study, the material properties which were obtained in previous study, the preparing process of the bearing strength test for a pinned joint CFRP composite plate subjected to in-plane loading at low temperature, and the FEM result of progressive damage model using ANSYS program are summarized to assess the structural safety of CFRP plate used in the magnetic supporting post of KSTAR(Korea Superconducting Tokamak Advanced Research).

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도시철도차량 유지보수 정보화 시스템을 위한 사고/고장 분류체계에 관한 연구 (A Study on the Failure of Classification for IT Maintenance System of Urban Transit)

  • 이호용;박기준;안태기;김길동;한석윤;이승일
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 추계학술대회 논문집(II)
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    • pp.259-264
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    • 2003
  • Failure code system must include data of maintenance history, classification of failure, affective range and situation when failure occur. But the present failure code system have used a simple code system for classification to include only merchandise and tools. Advantageously, expansional standard code system that will be developed, it make that users can take steps of standardized overhaul and inspection as proposal maintain contents when failure occur or something wrong in vehicle of urban transit. Standardized failure codes must be developed and used that manufacturing companies and urban transit operating companies in order to give effect to maintenance works.

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FTA(Fault Tree Analysis)기법을 이용한 이송용 대부하 베어링 고장 진단 (Fault diagnosis of walking beam roller bearing by FTA)

  • Bae, Y.H.;Lee, H.K.;Lee, S.J.
    • 한국정밀공학회지
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    • 제11권5호
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    • pp.110-123
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    • 1994
  • The development of automatic production systems have required inteligent diagnostic and monitoring function to repair system failure and reduce production loss by the failure. In order to perform accurate functions of intelligent system, inferencing about total system failure and fault analysis due to each mechanical component failures are required. Also the solution about repair and maintenance can be suggested from these analysis results. As an essential component of mechanical system, a bearing system is investigated to define the failure behavior. The bearing failure is caused by lubricant system failure, metallurgical defficiency, mechanical condition(vibration, overloading, misalignment) and environmental effect. This study described roller bearing fault train due to stress variation and metallurgical defficiency from lubricant failure by using FTA.

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Fracture simulation of SFR metallic fuel pin using finite element damage analysis method

  • Jung, Hyun-Woo;Song, Hyun-Kyu;Kim, Yun-Jae;Jerng, Dong-Wook
    • Nuclear Engineering and Technology
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    • 제53권3호
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    • pp.932-941
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    • 2021
  • This paper suggests a fracture simulation method for SFR metallic fuel pin under accident condition. Two major failure mechanisms - creep damage and eutectic penetration - are implemented in the suggested method. To simulate damaged element, stress-reduction concept to reduce stiffness of the damaged element is applied. Using the proposed method, the failure size of cladding can be predicted in addition to the failure time and failure site. To verify the suggested method, Whole-pin furnace (WPF) test and TREAT-M test conducted at Argonne National Laboratory (ANL) are simulated. In all cases, predicted results and experimental results are overall in good agreement. Based on the simulation result, the effect of eutectic-penetration depth representing failure behavior on failure size is studied.