• 제목/요약/키워드: Crack direction

검색결과 546건 처리시간 0.031초

스테인레스강 저주기 피로 수명 분포의 추계적 모델링

  • 이봉훈;이순복
    • 한국신뢰성학회:학술대회논문집
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    • 한국신뢰성학회 2000년도 춘계학술대회 발표논문집
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    • pp.213-222
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    • 2000
  • In present study, a stochastic model is developed for the low cycle fatigue life prediction and reliability assessment of 316L stainless steel under variable multiaxial loading. In the proposed model, fatigue phenomenon is considered as a Markov process, and damage vector and reliability are defined on every plane. Any low cycle fatigue damage evaluating method can be included in the proposed model. The model enables calculation of statistical reliability and crack initiation direction under variable multiaxial loading, which are generally not available. In present study, a critical plane method proposed by Kandil et al., maximum tensile strain range, and von Mises equivalent strain range are used to calculate fatigue damage. When the critical plane method is chosen, the effect of multiple critical planes is also included in the proposed model. Maximum tensile strain and von Mises strain methods are used for the demonstration of the generality of the proposed model. The material properties and the stochastic model parameters are obtained from uniaxial tests only. The stochastic model made of the parameters obtained from the uniaxial tests is applied to the life prediction and reliability assessment of 316L stainless steel under variable multiaxial loading. The predicted results show good accordance with experimental results.

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The rift Caves in Japan

  • Ogawa, Takanori
    • 동굴
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    • 제5호
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    • pp.37-52
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    • 1997
  • In Japan, on the volcanic line from Mt.Fuji to Hachijou Isl. in Pacific, we can see the many fissure erupted craters. The fissure eruption hasn't always left the rift caves. Recently I am investigated this era and recognized the rift caves. at Mt. Fuji 4. Miyake Isl. 3, Hachijou Isl. 3. The time of fissure eruption in Miyake Isl. make the long crack and gush the lava flow. But. we can see the rift caves only in the caldera. In the rift caves, we can see the thin coated lava on the scoria wall of the cavity and not only the side ways to extend by gasic pressure, on the surface of the earth. It is tow type rift caves. 1) The gas run to the side direction and built the cavities and after blowout the ground. 2) The gas built the cavity and then blowout the earth. I think that the thick scoria layers the most important factor and indispensable condition to built the rift caves.

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섬유시트로 보강된 RC 스래브의 실험적 연구 (An Experimental Study on RC Slab Strengthened with Fiber)

  • 이지용;최형석;김성도;정진환
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2007년도 정기 학술대회 논문집
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    • pp.519-524
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    • 2007
  • Recently, Fiber sheets have been used for strengthening the deteriorated reinforced concrete RC slabs because of its resistant capacity of corrosion and repairing works. The purpose of this study is to carry out the experimental studies on thirteen kinds of RC slabs and to investigate the behavior of RC slabs form the experimental results. Test parameters are the strengthening material, the number of sheet layer and strengthening direction. The behavior of strengthened He: slabs is represented by crack load-deflection curves and maximum load. And the parametric study based on the nonlinear FEM analysis are performed and its results are discussed.

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SMC 복합재료와 Carbon/Epoxy 복합재료의 파괴인성평가 (The Evaluation of Fracture Toughness of SMC Composite Material and Carbon/Epoxy Composite Material)

  • 최영근;이유태;이태순
    • 한국해양공학회지
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    • 제7권1호
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    • pp.25-32
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    • 1993
  • In composite materials, the fracture perpendicular to the fiber direction usually shows a non-linear behavior accompannying blunting and plastic deformation around the crack tip. In this study, the fracture thoughness in random short fiber SMC composite material and Carbon/Epoxy composite material is estimated by the A.M.(Area Method) and the G.L.M.(Generalized Locus Method) which can determine a stable total energy release rate(G$_T$) not only in highly elghly elastic material but also in highly non-linear materials.

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상용프로그램(ABAQUS)을 이용한 원전 격납건물 RC Panel의 극한 인장해석 (Ultimate Tensile Analysis of Reinforced Concrete Containment Panel by using ABAQUS Program)

  • 김남식;정대성;김광수
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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    • pp.577-584
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    • 2003
  • Tension tests of half-thickness concrete containment wall elements and material tests were conducted to derive a crack pattern and constitutive law of concrete. Main test variables are reinforcement ratio and the applied load ratio in two direction, and its effect on the behavior of reinforced concrete panel subjected to biaxial tension is investigated. Based on the test results, analytical expression is derived for the stress-strain relationship of concrete in tension. Ultimate analyses of reinforced concrete panels are carried out by a general purpose structural analysis computer program(ABAQUS), and its results are compared with the test results. The present analysis focuses on the effects of pre-analysis prior to test of specimens. These ultimate tensile analyses as pre-analysis are essential and important to design an effectual scheme of test.

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궤도형 전투차량의 궤도박리 발생 및 성장모드 예측에 관한 연구 (Separation Mode Analysis of Track Assembly of Main Battle Tank)

  • 이경호;박병훈
    • 한국군사과학기술학회지
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    • 제10권3호
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    • pp.173-180
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    • 2007
  • In this paper, we have proposed a simple finite element model for separation mode analysis on the roadwheel and track assembly of main battle tank and established a contact stress-based mechanism which could explain the initiation and growth of separation defect occurred during the test of padreplacable track. It was proved that the longitudinal contact shear stress component on the pin hole region of the track shoe body which is parallel to the driving direction is consistent with the crack initiation at the bonding surface between track shoe and wheel-side rubber. The longitudinal shear stress increased locally near the separated region after the separation initiated. So we could assume that the local stress concentration accelerates the separation growth according to the shear mode.

다이아몬드 공구의 회전원판내 응력 분산을 위한 슬롯 위치의 최적화 (Optimization of Slot Location for Stress Distribution in Rotating Disc of Diamond Tools)

  • 박성일;이상진;변서봉;황성택
    • 한국재료학회지
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    • 제15권9호
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    • pp.560-565
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    • 2005
  • The objective of this paper is to decide optimal of the slot angle to minimize stress concentration in rotating disc of diamond saw. The fracture phenomena of the slot are discussed by the theoretical and experimental approaches and then some recommendation are presented to prevent the fracture. The focus of this investigation is to evaluation the effect of the slot on stress distribution using optimum design technique and finite element method(FEM) analysis. Stress concentration of the slot with respect to the various parameter of the slot such position, size, number, rotation speed. From the experimental results, when the slot angle of diamond saw is located $8^{\circ}\~12^{\circ}$ from rotating direction, the maximum equivalent stress reduces.

Implement High Speed Bidirectional pulse power supply(BPPS) for plating

  • Kim, Tae-Eon;Park, Jong-Oh;Cho, Yong-Seong;Lee, Ihn-Yong;Kim, Young-Han;Lim, Young-Do
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.37.1-37
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    • 2001
  • Electric plating is used in various industry field. Specially, pulse plating is able to deposit material at high current density compared to conventional DC plating. For example, pulse plating can get more fine grain, can improve adhesion and metal distribution and current efficiency, can reduce internal stress and crack. Therefore, we developed bidirection pulse power supply(BPPS) which has high speed pulse current and high current density and improve deposition quality and increase plating speed in this paper. BPPS(Bidirection pulse power supply) needs high speed rising time, falling time and output current accuracy. BPPS consists of rectifier part, chopper part, invertor part, and control part. Rectifier part changes outprt current direction.

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Multilayered viscoelastic beam loaded in torsion under strain-path control: A delamination analysis

  • Victor I. Rizov
    • Advances in materials Research
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    • 제13권2호
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    • pp.87-102
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    • 2024
  • This paper is focused on the delamination analysis of a multilayered beam structure loaded in torsion under strain-path control. The beam under consideration has a rectangular cross-section. The layers of the beam are made of different viscoelastic materials which exhibit continuous inhomogeneity in longitudinal direction. Since the delamination is located inside the beam structure, the torsion moments in the two crack arms are obtained by modeling the beam as an internally static undetermined structure. The strain energy stored in the beam is analyzed in order to derive the strain energy release rate (SERR). Since the delamination is located inside the beam, the delamination has two tips. Thus, solutions of the SERR are obtained for both tips. The solutions are verified by analyzing the beam compliance. Delamination analysis with bending-torsion coupling is also performed. The solutions derived are timedependent due to two factors. First, the beam has viscoelastic behavior and, second, the angle of twist of the beam-free end induced by the external torsion moment changes with time according to a law that is fixed in advance.

변환각 트러스 모델에 의한 축력을 받는 철근콘크리트 부재의 전단강도 예측 (Shear Strength Prediction of Reinforced Concrete Members Subjected In Axial force using Transformation Angle Truss Model)

  • 김상우;이정윤
    • 콘크리트학회논문집
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    • 제16권6호
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    • pp.813-822
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    • 2004
  • 축하중을 받는 철근콘크리트 부재의 전단강도를 예측하기 위하여, 본 연구에서는 전단력과 축하중 및 휨모멘트를 받는 철근 콘크리트 부재의 전단거동을 예측할 수 있는 변환각 트러스 모델(TATM)을 제안하였다. TATM에서, 축력의 영향을 고려하기 위하여 축압축력이 증가할수록 고정각은 감소하며 균열 방향의 콘크리트 전단저항은 증가한다. TATM의 예측결과가 축력을 받는 철근콘크리트 부재에 대하여 정확성과 신뢰성을 가지는지 검증하기 위하여, 축력을 받는 총 67개의 전단실험 결과를 수집하였으며, TATM 및 기존의 트러스 모델(MCFT, RA-STM FA-STM)과 비교하였다. 수집한 실험결과와 해석결과를 비교한 결과, TATM에 의한 해석결과는 실험결과를 평균 0.95, 변동계수 $12.0\%$로 기존의 트러스 모델보다 더 정확히 예측하였으며, 철근능력비, 축력, 전단경간비 및 압축철근비의 영향을 받지 않았다.