リスク解析援用型構造健全性保証のための溶接配管の残留応力推定手法の提案（第1報：測定データの前処理による精度向上）

抄録

In welded structures, it is indispensable to evaluate welding residual stresses for assurance of structural integrity. Today, several nondestructive evaluation methods of residual stresses have been proposed, however measured results can not be applied to the FEM (Finite Element Method) analysis. For the FEM applications, all the 6 components of stresses in the whole structure must be estimated and those solutions should satisfy the self-equilibrium condition. From this view point, authors have proposed the bead flush method. In this method, welding residual stresses are calculated nondestructively by a simple elastic FEM analysis from eigen-strains which are estimated by the inverse analysis from released strains during removal of reinforcement of the weld. By now, the effectiveness of this method has been proved for welded plates and pipes with relatively high bead height. As decreasing bead height down to below one mm level, however, it is difficult to satisfy both high accuracy and stability because of higher effect of measurement error. In this study, to obtain multiple residual stress distribution from a single measurement, released raw strain data were pre-treated in consideration of a prior knowledge before conducting the inverse analysis.