T型パイプ継手の歪詳細解析と疲労亀裂発生寿命予測

概要

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The experimental analysis was performed to study fatigue lives of the tubular T-connections with three types of welds, that is, concave, flat faced, and convex type of welds, and a physical meaning about failure life of tubular connections is considered. The computer program system using the finite element method is developed to analyze the tubular connections. In this system a nonlinear shell analysis program and a nonlinear solid analysis program are combined by using zooming technique. Very fine mesh subdivision is adopted to obtain accurate stress and strain distribution in the vicinity of the weld toes, where the high strain concentration occurs. The following results are obtained, from this study. 1) The region where the high strain concentration occurs is restricted to microscopic area in the vicinity of the toe of the welds. 2) Plane strain approximation is approval for designer to analyze the tubular T-connections. 3) Multiaxial or biaxial strain criterion should be adopted to evaluate fatigue lives of tubular connections. 4) A concept of minimum volume for fatigue damage is used to define effective strain. Using this effective strain, crack initiation lives of the tested models can be predicted with good accuracy.
社団法人日本船舶海洋工学会の論文