• Title/Summary/Keyword: 인장 전단 시험

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Shear Strength of lnconel Tube Welded with Pulsed Nd:YAG Laser (펄스형 Nd:YAG레이저로 용접된 Inconel Tube의 전단강도)

  • Chang, W.;Kim, J. D.;Chung, J. M.;Kim, C. J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.125-128
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    • 1995
  • The remote sleeve repair-welding technology using the pulsed Nd:YAG laser for increasing the lifetime of the steam generator tube in the nuclear power plant has been developed. The laser welding has many advantages on deep penetration depth and narrow heat affect zone(HAZ). The inconel 600 tube and inconel 690 sleeve used high temperature and high pressure service have been welded as round lap welds. It is found that the relation between the connection width and welding parameters. It is found that the shear strength in proportion to the connection width by conducting tensile-shear tests.

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The Characteristics of Fatigue Crack Propagation Behavior in Shear Load (전단하중 하의 피로균열 전파거동의 특징)

  • Lee, Jeong-Moo;Song, Sam-Hong
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.302-307
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    • 2004
  • This paper reviewed characteristics of fatigue crack behavior observed by changing various shapes of initial crack and magnitudes of loading in compact tension shear(CTS) specimen subjected to shear loading. In the high-loading condition, fatigue crack under shear loading propagated branching from the pre-crack tip. Meanwhile, the secondary fatigue crack in the low-loading condition which was created in the notch root due to friction on the pre-crack face grew to a main crack. Influenced by the mode II loading condition, fatigue crack propagation retardation appeared in the initial propagation region due to the reduction of crack driving force and friction on crack face. In both cases, however, fatigue cracks grew in tensile mode type. Propagation path of fatigue crack under the shear loading was 70 degree angle from the initial crack regardless of its shape and load magnitude.

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A study on the characteristics of multi load transfer ground anchor system (다중정착 지반앵커의 하중전달 특성에 관한 연구)

  • Kim, Ji-Ho;Jeong, Hyeon-Sic;Kwon, Oh-Yeob;Shin, Jong-Ho
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.1
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    • pp.25-50
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    • 2014
  • In order to identify a load transfer mechanism of ground anchors, the behavior of multi load transfer ground anchor systems was investigated and compared with those of compression type anchors and tension type anchors. Large scale model tests were performed and stress-strain relationships were obtained. The load transfer mechanism of ground anchors was also investigated in the field tests. Finally, numerical analyses to predict the load-displacement relationships of anchors were conducted. It is concluded that the load transfer characteristics of MLT anchors are mechanically much more superior in the pull-out resistance effect than those of existing compression and tension type anchors. From the results of research work, we could suggest that the max pull-out capacity of anchor capacity to each the soil condition. Also, the MLT anchors can be used to achieve both structural enhancement and economic construction in earth retaining or supporting structures.

저항용접 시뮬레이션을 이용한 가공전극 적용 용접 특성 평가

  • Lee, Sang-Min;Choi, Du-Youl;Park, Yeong-Do
    • Proceedings of the KWS Conference
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    • 2010.05a
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    • pp.97-97
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    • 2010
  • 최근 자동차에서 경량화의 방안으로써 높은 강성을 요구하는 고장력강 사용이 증대 되고 있다. 그러나 고장력강은 저항 점용접 시 일반 강에 비해 높은 전류를 요구하며 계면파단 및 expulsion 발생이 용이하기 때문에 가용 전류 구간이 좁은 특성을 가진다. 많은 연구자들이 hold time, tempering 등의 process를 이용하여 고장력강의 저항 점용접성을 개선하고자 하였으나 생산 공정라인에 적용하기는 어려운 실정이다. 본 연구에서는 용접 공정 변수의 변화에 따른 용접성과 전극 형상 변화을 통한 고장력강 점 용접성 향상에 대한 연구를 실시 하였다. 고장력강의 점 용접성 비교하기 위해 표준 전극(S1)과 인위적으로 가공한 전극(M1)을 사용하였으며, 실험에 사용된 판재는 두께 1.4mm의 DP590이며, 그 결과 표준전극(S1) 보다 가공 전극(M1)의 가용 전류 구간이 0.5kA 정도 넓은 것으로 확인 되었다. 두 전극을 사용한 점용접 시험편들의 인장전단강도를 비교 해보면 표준전극(S1)을 적용한 점용접 시 인장전단강도는 KS B 0850 기준에 만족하나 계면 파단이 발생 하였다. 가공 전극(M1)을 적용한 점용접 시 인장전단강도는 규격 기준에 만족하나 버튼 파단이 발생 하였다. 두 전극을 적용한 점용접부 형상 및 용접부 온도 분포에대해 저항점용접 시뮬레이션 프로그램(SORPAS)을 이용하여 실험 결과 값과 비교 분석하였고 파단모드의 변화에 대한 원인 분석을 도출 하였다.

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Temperature Dependence of Tensile Properties in Single Crystal Superalloy CMSX-4 (단결정 초내열 합금 CMSX-4의 온도에 따른 인장특성의 변화)

  • Baig-Gyu Choi;Jeonghyeon Do;Joong Eun Jung;Sangwon Lee;In Soo Kim
    • Journal of Korea Foundry Society
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    • v.44 no.3
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    • pp.59-69
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    • 2024
  • The tensile properties of the single crystal superalloy CMSX-4 were examined at various temperatures. In the heat-treated state, some portion of the eutectic γ-γ' remained, and a uniform cuboidal γ' particles existed across the entire material. The yield strength and tensile strength reached highest at 750℃ and decreased with raising testing temperature. The elongation was lowest at 650℃ due t℃oncentrated deformation near the fracture area. However, the elongation increased at higher temperatures due to uniform deformation throughout the entire specimen. Fracture surface analysis tested at 850℃ and 950℃ revealed that cracks originated from casting defects. TEM observations conducted after the tensile test indicated that the primary deformation mechanism at room temperature involved dislocation shearing within the γ' phase. However, the increased strength both at 750℃ where stacking faults generated and at 650℃ was caused by the increased resistance of γ' phase to dislocation. The strength decreased because the movement of dislocations became easier due to the thermal activation process at and above 850℃.

Determination of Flow Stress of Zircaloy-4 Under High Strain Rate Using Slot Milling Test (슬롯밀링시험을 이용한 높은 변형률 속도 조건하에서 Zircaloy-4의 유동응력 결정)

  • Hwang, Jihoon;Kim, Naksoo;Lee, Hyungyil;Kim, Dongchoul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.1
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    • pp.67-75
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    • 2013
  • The flow stress of zircaloy-4 used in the spacer grid supporting a nuclear fuel rod was determined by the Johnson-Cook model, and model parameters were determined using reverse engineering. Parameters such as A, B, n and ε˙0 were determined by the tensile test result. To obtain the parameters C and m, a slot milling test and numerical simulation were performed. The objective functions were defined as the difference between the experimental and the simulation results, and then, the parameters were determined by minimizing the objective function. To verify the validity of the determined parameters, cross-verification for each case was conducted through a shearing test and simulation. The results tend to show agreement with the experimental results, such as the features of sheared edges and maximum punch force, with the correlation coefficients exceeding at least 0.97.

Inplane Shear Material Properties of Unidirectional Carbon Fiber Reinforced Aluminum Laminate Composites (일 방향 탄소섬유 강화 알루미늄 적층 복합재료의 전단물성치 측정에 관한 연구)

  • Baek, Un-Cheol;Cho, Maeng-Hyo;Hawong, Jai-Sug
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.10
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    • pp.2114-2121
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    • 2002
  • In order to study the effects of oblique tabs on the in-plane shear properties of unidirectional carbon fiber reinforced aluminum laminate composites, the 10off-axis tensile test, the 45 off-axis tensile test and Iosipescu shear test were performed to determine the shear properties. Off-axis tension test was studied by using new oblique-shaped tabs proposed by Sun and Chung(7). Iosipescu shear test was studied by using modified Wyoming test fixture. The oblique tabs reduced remarkably end-constraint effects of off-axis specimens with a aspect ratio of about eight. The experimental results show that there is no significant difference between off-axis test results and those of Iosipescu shear test. The 45off-axis tensile tests are recommended for the determination of the shear properties of unidirectional carbon fiber reinforced aluminum laminated composites.

An Experimental Study on the Mechanical Properties of High Modulus Carbon-Epoxy Composite in Salt Water Environment (염수 환경에 노출된 고강성 탄소/에폭시 복합재의 물성치 변화 연구)

  • Moon, Chul-Jin;Lee, Cheong-Lak;Kweon, Jin-Hwe;Choi, Jin-Ho;Jo, Maeng-Hyo;Kim, Tae-Gyeong
    • Composites Research
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    • v.21 no.6
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    • pp.1-7
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    • 2008
  • The main objective of this study is to investigate the effect of salt water on the mechanical properties of a high modulus carbon-epoxy composite. Specimens were made of a carbon-epoxy composite UPN139B of SK Chemical and tested under inplane tension and shear after 0, 1, 3, 6, 9, and 12 months immersion in 3.5% salt water. Acceleration technique such as temperature elevation was not used. The tensile strengths and modulli in fiber and matrix direction did not show any remarkable degradation until 12 months immersion. In contrast to the tensile properties, shear strength and modulus started to gradually decrease up to about 10% of values of dry specimens after 12 months immersion. It was confirmed through the test that the material UPN139B can be an effective material for the shell structures in salt water to resist against the external pressure buckling because of the high fiber directional modulus and corrosion resistance.

Study on Mechanical Properties of Rice Culm (벼줄기의 기계적(機械的) 특성(特性)에 관(關)한 연구(硏究))

  • Hur, Yun Kun;Lee, Sang Woo
    • Korean Journal of Agricultural Science
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    • v.9 no.2
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    • pp.569-575
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    • 1982
  • Mechanical properties of rice plants were tested to determine compressive force, bending force, tensile force and shear force for improvement of harvesting machines and for efficient utilization of rice culm during the proper harvesting period. Rice varieties used in this study were two Japonica varieties with Irri 348 and Jinju, and two Indica×Japonica hybrids with Seogwang and Taebaeg, which were grown in the standard fertilization field of Chungnam Rural Development Office. Also Jinju and Taebaeg were tested to elucidate the shearing characteristics which included shear force-strain relationship, shear force and shear energy according to the position from the ground level, the shearing angle to the rice culm, and the moisture content. 1. Compressive force, bending force, tensile force and shear force were higher In Japonica varieties than Indica×Japonica hybrids. 2. Shear force to overall culm length decreased progressively to upper positions in Jinju variety but a constant shear force was approximately showed between the ground level and the position of 21cm in Taebaeg variety. 3. Shear force and shear energy increased with increase of the cross sectional area, and the rates of increase were high in general up to the cross sectional area of 10mm2 and then they became dull very much. 4. Shear force and shear energy decreased with decrease of moisture content of rice culm after cutting up to the moisture content of 60% (w. b.) and then they did not change significantly.

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Nondestructive Evaluation for Grain Refinement of Aluminum Alloy of Equal-Channel Angular Pressing (ECAP 가공한 알루미늄합금의 결정립 미세화에 대한 비파괴평가)

  • Ahn, Seok-Hwan;Nam, Ki-Woo;Kim, Jin-Hwan;Kang, Suk-Bong
    • Journal of the Korean Society for Nondestructive Testing
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    • v.22 no.2
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    • pp.132-139
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    • 2002
  • The grain size of aluminum alloy was refined to the submicrometer level by using equal-channel angular pressing(ECAP). The effect of grain size refinement was evaluated by the tensile test, micro-hardness test, microstructure observations, ultrasonic test and acoustic emission test. The strength and the Vickers hardness were increased significantly according to grain size refinement after equal-channel angular pressed. The ultrasonic velocity was faster after equal-channel angular pressed, and the high frequency range appeared. The results of the ultrasonic velocity and the frequency range are expected to be basic data that can prove the grain size refinement