• 제목/요약/키워드: Residual stress distribution

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단섬유 복합재료 사출성형물의 잔류응력 측정 (Measurement of Residual Stress Distribution in Injection-Molded Short Fiber Composites)

  • 김상균;이석원;윤재륜
    • 한국복합재료학회:학술대회논문집
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    • 한국복합재료학회 2001년도 추계학술발표대회 논문집
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    • pp.61-63
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    • 2001
  • Residual stress distribution in injection-molded short fiber composites was determined using layer-removal method. Polysterene with 3 vol% carbon fibers was injection-molded into the tensile specimen. With milling machine layer-removal process was conducted and the curvature data were acquired. Treuting and Read analysis which is assuming isotropic material, and White analysis considering anisotropy due to the fiber orientation were used to calculate residual stress of the flow direction through the thickness direction and compared with each other.

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용접부의 천공 측정법에 의한 잔류 응력에 관한 연구 (A Study on the Residual Stresses by the Hole Drilling Measuring in the WeldZone)

  • 남궁재관
    • 한국공작기계학회논문집
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    • 제17권3호
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    • pp.115-121
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    • 2008
  • A knowloedge of the residual stress distribution at circumferential welds can increase the prediction accuracy of a fracture assessment in pipe lines. In this study, in order to predict the residual stress distribution in the circumferential butt-welded pipes were measured, using the hole-drilling strain gauge method. Their practical applications were performed in to two kinds of pipes. As the results, the following characteristics were found. On the inner surface of pipes, the circumferential and axial residual stresses were both tensile near the center line of welding and both of them changed from tensile to compressive as the distance from the center line increased. On the outer surface, however, the circumferential residual stress was shown to be tensile wile the axial residual stress was compressive near the center line of welding, and later they were revered at the region far away from the centerline.

와이어 방전 가공 시 발생되는 열응력 분포에 관한 유한요소법적 고찰 (A study on the Thermal Stress Distribution for Wire Electrical Discharge by Finite Element Method)

  • 반재삼;김승욱;김선진;조규재
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2002년도 추계학술대회 논문집
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    • pp.210-213
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    • 2002
  • The Purpose of this study is to know temperature and thermal stress distribution in specimens during processing of WEDM. If it is constant to the cutting speed and the thickness of material, it is very important to the effect of temperature and the thermal stress distribution after cutting processing. This paper show the analysis result of the distribution of temperature and the residual stress along the direction of thickness before processing of WEDM and after when the cooling temperature is$20^{\circ}C$. The maximum temperature of edge of specimens is $1600^{\circ}C$. It has little temperature gradient in the depth which is 5mm away from edge of specimens. Equivalent residual stress is result in 180.7 MPa at maximum temperature.

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파이프 원주방향 용접부의 잔류응력분포 특성에 관한 실험적 연구 (An Experimental Study on the Residual Stress Distribution at Circumferential Welds in Pipes)

  • 남궁재관;홍재학
    • 한국정밀공학회지
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    • 제8권1호
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    • pp.41-49
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    • 1991
  • A knowledge of the resdual stress distribution at circumferential weldments can normally increase the accuracy of a fracture assessment in pipe line. In this paper, we present the measurements about the residual stress distributions at three kinds of circumferential butt welded pipes using the holl drilling strain gage method. By this experiment, we have obtined the following characteristics. At the inner surface of the pipe region near the center line of welding is under high tensile residual stress. However, as the distance from the center line of welding increases, the tensile component decreases and finally becomes compressive residual stress at region far away from the center line of welding. The longitudinal residual stress at the outer surface is compressive regardless of the diameter of pipe and the circumferential stress is changed from compressive to tensile as pipe diameter increases. The results also demonstrate that the residual stress is mainly caused by self-restraint bending force in the pipe welding.

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상수도용 도복장간관의 용접 및 외부하중에 의한 응력 특성에 관한 연구(II) - 복합외부하중 및 후열처리에 따른 용접부의 응력분포 특성 - (A Study on the Stress Distribution of Steel Water Pipes(II) - Characteristics of Stress Distribution by External Forces and PWHT -)

  • 윤석환;이승기;나석주;고명환
    • Journal of Welding and Joining
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    • 제19권3호
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    • pp.292-297
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    • 2001
  • One of the major characteristics that affects the life of welded steel water pipes is the stress distribution caused by welding and external forces. Some studios have bean carried out on the residual stress of steel water pipes. But the results on the stress distributions by welding and complex external forces are rare, because real water pipes operate under the ground and many kinds of external forces act simultaneously on the joints. To understand the complex stress distributions of welded joints, therefore predictions by numerical or analytic methods are required. In this study, temperature and stress distributions in steel water pipes produced by welding are predicted by a three-dimensional finite element method(FEM). Based on these results, stress distributions by welding and complex external forces are evaluated by adopting the same numerical method. The influence of some post weld heat treatments on residual stress distributions is also investigated.

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유한요소법을 이용한 용접부의 열전달 및 잔류응력 해석에 관한 연구 (A Study on Analysis of Heat Transfer and Residual Stress on the Weld Zone using FEM)

  • 김일수
    • 한국생산제조학회지
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    • 제9권5호
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    • pp.96-104
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    • 2000
  • This paper represents to develop a computer software system which is capable to analyze the phase transformation of high strength steel(BV-AH32) and to predict heat transfer and welding residual stress due to phase transformation during Gas Metal Arc(GMA) welding. The developed model was considered temperature dependent properties such as young's modules, coefficient of thermal expansion and yield stress as well as the double ellipsoidal heat distribution by the moving arc. From the results, it was found that the longitudinal and transverse residual stresses calculated by the coupled analysis of heat transfer, residual stress and phase transformation showed good agreement with the experimental data. In addition, the temperature distribution as well as longitudinal and transverse residual stresses of weldment by the 1-pass and 2-pass of welding were also determined.

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알루미늄 합금 용접재의 피로파괴에 미치는 잔유응력의 영향에 관한 연구 (A Study on the Influence of Residual Stresses on Fatigue Fracture of Aluminum Alloy Weldments)

  • 차용훈
    • 한국생산제조학회지
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    • 제4권4호
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    • pp.25-32
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    • 1995
  • This study is to inspect the influence of the initial residual stress on fatigue crack growth behavior after the distribution of the initial residual stress is measured when the crack is growing from the compressive residual stress field. Also, the tensile residual stress field. Also, the influence of the variation of residual stress distribution on fatigue crack growth behavior at the crack tip is studied when the initial crack occurs on weld metal, bead interface and HAZ (Heat Affected Zone), respectively. For this purpose, CT-type specimen that crack parallel to the welding bead were manufactured by butt welding on the Al. Alloy 1100-O plate.

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PREFLEX BEAM 제작시의 용접부 역학적 특성에 관한 연구 (The Study on the Analysis for Welding Residual Stress of Preflex Beam)

  • 방한서;주성민;김규훈;이창우;이형훈
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2002년도 추계학술대회 논문집
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    • pp.323-328
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    • 2002
  • Since the pre flex beam is fabricated by welding, the precompressive stresses that should occur over the concrete pier are diminished by the welding residual stresses. Therefore the welding residual stresses must be relieved during the fabrication. So the analysis and examination of the accurate welding residual stress distribution characteristic are necessary. On this study, accurate distribution of welding residual stress of preflex beam is analyzed by finite element method.

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균열 진전에 따른 잔류응력 재분포 해석을 위한 수치해석 모델링 (Numerical Modeling for the Analysis of Residual Stress Redistribution due to Crack Propagation)

  • 송하철;이창현;장창두
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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    • pp.245-251
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    • 1999
  • As the crack grows in the residual stress fields, the distribution of the residual stress is changed. In this study, a finite element modeling technique is developed to simulate the redistribution of residual stress due to crack propagation. To certify the accuracy, the crack propagation tests were carried out and tile effective stress intensity factor range was evaluated considering the redistribution of residual stress from the FE analysis.

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