三次元有限要素解析による管フランジのボルト締付け順序の評価

概要

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Scatter in bolt axial stresses, when tightening a pipe flange with a number of bolts, is of critical problem. Bibel et al. recently proposed both experimental and numerical methods to give uniform bolt axial stresses at the completion of tighening operation. However, their method is not so attractive from the practical point of view because it needs preparatory experiments and it also involves some restrictions in executing numerical analysis. In this study, a numerical approach is proposed, which can efficiently evaluate the scatter in bolt axial stresses using FEM as a threedimensional elastic contact problem, and its validity is ascertained by experiment. Specifically, the scatter in bolt axial stresses generated at the completion of tightening operation is estimated, when tightening each bolt one by one with equal axial stress. In addition, it is also investigated how much initial bolt stresses are needed to achieve uniform axial bolt tension in the final state. The analytical objects are pipe flanges specified in JIS B 2238.
1998-11-25