Numerical Investigation of Collapse Moment of Deformed Pipe Bends Subjected to Internal Pressure and Bending Moment

Abstract

AbstractThe pipe bends are manufactured from the pipe bending process, and during the process, the circular cross-section is deformed into noncircular cross-section. The cross-section difference affects the collapse moment due to a change in moment of inertia of the pipe bend about its axis of rotation. The changes in the cross-section of pipe bends are defined as initial geometric imperfection. The present paper investigates the 45°, 90° and 135° actual deformed pipe bends subjected to internal pressure and in-plane closing moment. The present study is simulated using three-dimensional finite element analysis accounted for the large geometry change effect. The modeling of pipe bends incorporated with geometric imperfection is created using Python language. The material models considered for the analysis are elastic-perfectly plastic and strain-hardening. The collapse moment of circular pipe bend is compared with initially imperfect pipe bends and found that the effect of geometric imperfection on collapse moment of pipe bends is significant and should be incorporated in the analysis.KeywordsPipe bendGeometric imperfectionCollapse momentInternal pressureIn-plane closing moment