Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
SIF FOR TRUNNION PIPE SUPPORT: A COMPARISON BETWEEN FEA DATA AND ASME B31J WITH FOCUS ON LARGE BORE PIPES
Submission Author:
LUIS FERNANDO MOURA , SP , Brazil
Co-Authors:
MARIA LUIZA SCORALICK SALDANHA, LUIS FERNANDO MOURA
Presenter: MARIA LUIZA SCORALICK SALDANHA
doi://10.26678/ABCM.COBEM2023.COB2023-0233
Abstract
This study focuses on the determination of Stress Intensification Factors (SIFs) for Trunnion pipe supports welded to large bore straight pipes. Trunnions are widely used in industry to control the vertical displacement of the pipe and minimize stresses, consisting in a cylinder (usually a pipe) attached to the Run Pipe. In 2017 ASME B31J standard has been published with SIF values based on empirical and numerical data. However, there is a lack of data for Trunnion pipe supports, since the B31J establishes SIF values for branches connections and not for “hollow circular cross section welded attachments”, as Trunnions are. Specialized pipe stress software, such as Caesar II, due to the lack of standardized data, assume SIF value to be one when it is not manually inputted, which can result in underestimated allowable stresses for the fatigue problem. The research aims to investigate whether B31J could be applicable for the Trunnion pipe support problem through data originated from FEA simulations, and the creation of a data base for the development of a low-cost, quick, and trusted tool to check Trunnion pipe supports, reducing study time by avoiding the use of expensive software, and providing data for specialized pipe stress software. The study covers pipes ranging from 30 to 80 inches in diameter and Trunnions from 16 to 40 inches. The model considers a Trunnion with no reinforcement pad attached to a straight pipe, where one of the Run Pipe ends is fixed (anchored) and the other one has no restriction of movements. The methodology includes using the NozzlePro software to obtain SIF values, whose fatigue model is based on empirical data supported by WRC 329's recommendations. The results demonstrate that SIFs are modified by the geometry of the Trunnion / Run Pipe and are independent of loading conditions. The study compares SIFs obtained using FEA and ASME methodologies and the results demonstrate that the SIF In-Plane type from B31J is conservative for Trunnions while the Out-Plane type is non-conservative for some configurations of Run Pipe / Trunnion, and caution should be adopted when using B31J as a first approximation.
Keywords
Pipe supports, Stress Analysis, Stress Intensity Factor, SIF, Trunnion Pipe Support, Large Bore Pipes
