Development of Design Formulas for Pipe Loops Used in Ships Considering the Structural Characteristics of Curved Portions

doi:2012.26.5.87

J. Ocean Eng. Technol. > Volume 26(5); 2012 > Article

J. Ocean Eng. Technol. 2012;26(5):87-93.
DOI: https://doi.org/10.5574/KSOE.2012.26.5.087

Park Chi-Mo,Bae Byoung-Il

School of Naval Architecture and Ocean Engineering University of Ulsan,Hyundai Heavy Industry Co. Ltd.

곡선부의 구조 특성을 고려한 선박용 파이프 루프 설계식 개발

박치모,배병일

울산대학교 조선해양공학부,현대중공업(주) 해양사업본부

Keywords: Pipe loop, Design formula, Curvature of corners, Bending deformation correction factor, Bending stress correction factor, Finite element analysis

핵심용어: 파이프 루프, 설계식, 코너부 곡률, 굽힘 변형 수정계수, 굽힘 응력 수정계수, 유한요소해석

Abstract

Many longitudinally-arranged pipes in ships are equipped with loops as a measure to reduce stresses caused by displacement loads conveyed from the hull girder bending and/or thermal loads of carried fluid of non-ambient temperature. But as the loops have some negative effects such as causing extra manufacturing cost and occupying extra space, the number and the dimensions of the loops need to be minimized. In the meanwhile, a design formula for pipe loops has been developed by modeling them as a spring element of which stresses and axial stiffness are calculated based on the beam theory. But as the beam theory turns out to be inappropriate to deal with the complex structural behavior in the curved corner portion of the loop, this paper aims at improving the previously developed design formula by adopting correction factors which can allow for the gap between the results of beam theory and a more accurate analysis. This paper adopts a finite element analysis with two-dimensional shell elements with some validation work for it. The paper ends with a sample application of the proposed formulas showing their accuracy and efficiency.