The Development of Design Formulas for Pipe Loops Used in Large Vessels (I)

J. Ocean Eng. Technol. 2008;22(5):132-137.

Park Chi-Mo,Yang Park-Dal-Chi,Lee Jong-Hoon

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

대형 선박의 파이프 루프 설계식 개발 (I)

박치모,양박달치,이종훈

울산대학교 조선해양공학부,울산대학교 조선해양공학부,현대중공업(주) 기본설계¹부

Keywords: Pipe loop, Longitudinal bending of ships, Displacement load, Pipe stiffness, Shear deflection, Design formula

핵심용어: 파이프 루프, 선체 종 굽힘, 변위 하중, 파이프 강성, 전단 처짐, 설계식

Abstract

Ship structures are subject to severe environmental loads causing appreciable hull girder bending which in turn affects the piping system attached to the main hull in the form of a displacement load. While this load may cause failure in the pipes, loops have been widely adopted as a means of preventing this failure, with the idea that they may lower the stress level in a pipe by absorbing some portion of the displacement load. But since such loops also have some negative effects, such as causing extra manufacturing cost, deteriorating the function of the pipe, and occupying extra space, the number and dimensions of the loops adopted need to be minimized. This research developed design formulas for pipe loops, modeling them as frames composed of beam elements, where not only bending but also shear deflection is taken into account. The accuracy of the proposed design formulas was verified by comparing two results respectively obtained by the proposed formulas and MSC/NASTRAN. The paper concludes with a sample example showing the efficiency of the proposed formulas.