Investigation on structural integrity of shape distorted 90° back-to-back pipe bends under in-plane closing bending moment

Abstract

Purpose

The aim of this study is to ensure the structural integrity of 90° back-to-back (B2B) pipe bends by developing a closed-form numerical solution for estimating the collapse load of shape distorted 90° B2B pipe bends using non-linear finite element (FE) analysis.

Design/methodology/approach

The collapse behaviour of 90° B2B pipe bends with ovality (C_o) and thinning (C_t) has been evaluated by non-linear FE approach. Moment load is applied in the form of in-plane closing moment (IPCM). The current FE approach was evaluated by the numerical solution for the plastic collapse moment of pipe bends, which has been published in the literature. The collapse moments were obtained from the twice elastic slope (TES) method using the moment-rotation curve of every individual model.

Findings

The implication of C_t/C_th on collapse load is found to be highly insignificant in terms of increasing bend radius and C_o. C_o weakens the geometry, and its effect on the collapse load is substantial. A closed-form numerical solution has been proposed to calculate the collapse load of 90° B2B pipe bend with shape imperfections.

Originality/value

The implications of shape distortion (C_o and C_t) in the failure analysis (collapse load) of 90° B2B pipe bends has not been investigated and reported.

Citation

Vinothkumar, A., Veerappan, A. and Shanmugam, S. (2022), "Investigation on structural integrity of shape distorted 90° back-to-back pipe bends under in-plane closing bending moment", Multidiscipline Modeling in Materials and Structures, Vol. 18 No. 2, pp. 291-307. https://doi.org/10.1108/MMMS-01-2022-0004