• Title/Summary/Keyword: 유효 노치응력법

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Estimation Fatigue Life of Weldments by Notch Stress Approaches (노치응력법에 의한 용접 연결부 피로수명 추정에 관한 연구)

  • Yang, Park-Dal-Chi;Song, Joon-Kyu
    • Journal of Ocean Engineering and Technology
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    • v.25 no.5
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    • pp.47-51
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    • 2011
  • This paper analyzes the fatigue-life of welded joints using the notch stress approach. In the notch stress approach, the notch effects are usually approximated by introducing weld-bead parameters for the local detailed weld joints. The actual bead shape is complex and 3-dimensional. It may also greatly influence the fatigue strength. In this study, the welded shape was modeled using a 3D-scanner. The critical distance method was adopted in the evaluation of the fatigue effective notch stress for the weldments. Fatigue life tests were performed to verify the present method of fatigue life estimation for two types of welded plates with longitudinal attachments. The estimated results of the present methods were applied to the results of the experiment. The results of the analysis showed that the scatter of fatigue-life for the experimental data expressed in the nominal stress was significantly reduced by applying the effective fatigue stress of the present study.

Fatigue Assessment of High Strength Steel with Butt Welded Joints for the Root Gap Difference (고강도강 맞대기 용접 시험편의 루트갭 변경에 따른 피로강도 평가)

  • Kim, Ho-Jung;Kang, Sung-Won;Kim, Myung-Hyun
    • Journal of the Society of Naval Architects of Korea
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    • v.48 no.1
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    • pp.56-61
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    • 2011
  • In this study, a series of fatigue tests was conducted to evaluate fatigue strength for the root gap difference with high strength steel with butt welded joints. A finite element analysis using effective notch stress method was also performed to compare effective notch factors each other with butt welded specimens made by copper backing. The results of fatigue tests were classified according to the root gap difference. Fatigue life of butt welded specimens is presented for determining the root gap of high strength steel with butt welded joints in terms of fatigue strength. Then effective notch stress was applied to interpret fatigue strength of butt welded specimen model which is reflected actual measured dimensions. As a result, fatigue strength of high strength steel with butt welded specimens is increased by root gap gets longer in length.