Quantification of elastic stresses for structurally distorted 90° very thin-walled pipe bends under in-plane bending

Abstract

PurposeElastic stress solutions are required in the field of fracture mechanics and the analysis of creep failure. The published precise elastic solutions are not addressing the influence of the manufacturing process induced, inevitable cross sectional deviations called ovality and thinning. The influence of ovality on plastic limit and collapse loads are reported in literature. Hence, it is important to study the combined effect of ovality and thinning on elastic stresses of bends.Design/methodology/approachThis paper relies on elastic finite element evolutions of stress components– longitudinal membrane stress, longitudinal bending stress, circumferential membrane stress and circumferential bending stresses. Based on the results, the coefficients for the equations are also obtained through the regression analysis.FindingsNew analytical solutions are prescribed to estimate the elastic stresses at the mid-section of the 90° very thin-walled bend with ovality and thinning, when subjected to in-plane bending moment. The ovality has significant influence on elastic stress whereas the thinning is not so. The proposed equations give an accurate estimation of elastic stresses at the mid-section of the bend with the incorporation of the parameters, namely R/rm, rm/t and ovality.Research limitations/implicationsThe influence of shape imperfections, namely ovality and thinning on elastic stress of 90° very thin-walled bends having rm/t > 20, subject to in-plane bending moment is proposed.Originality/valueThe influence of shape imperfections, namely ovality and thinning, on elastic stress of 90° very thin-walled bends with rm/t > 20, subject to in-plane bending moment is proposed.