매개변수 적용범위를 확장한 배관 곡관부에 용접 부착된 원형관 이음부의 이차응력지수

Abstract

The stress concentration of the integral welded attachments (IWA) often used to support piping system has been a big issue because it induces local stresses in piping. Trunnions and lugs are the typical welded attachments widely used on piping system in many ways. In a piping system, these attachments are often installed on elbows as well as on straight pipe. The method to evaluate local stresses associated with attachments on elbows has been suggested in EPRI TR-107453. However, there are limitations regarding specific parameters range in order to use correlation equation calculating the secondary indices each direction. In this paper, parametric study based on piping elbow size and attachment dimension was performed utilizing finite element analysis (FEA) to evaluate the secondary stress indices of hollow circular cross section welded attachments on piping elbows with the extended parameters range. The results of the FEA were used to develop correlation formulas for calculating secondary stress indices. The empirical equations developed in this study are suggested as an alternative evaluation method of EPRI TR-107453 by extending parameters range of attachments on piping elbows.