An optimisation design method for cryogenic pipe support layout of LNG-powered ships

Abstract

For LNG-Powered ships, cryogenic pipe bears ultralow temperature load; the stress of LNG pipe is very sensitive to the layout of pipe supports. In order to improve the safety of LNG pipe under complex loads, an optimisation design method for cryogenic pipe support layout (ODMCPSL) of LNG-Powered ships is proposed in this paper. The objective of ODMCPSL is to deduce the structure stress, and both the pipe supports number and their positions are taken as variables. An improved genetic algorithm named Genetic Assimilation-Genetic Algorithm (GA-GA) is adopted in ODMCPSL, in which a new factor named magnetic factor (MF) is introduced in mutation operation and the number of pipe supports is optimised by MF. In the algorithm, the number and positions of the pipe supports can be optimised at the same time. ODMCPSL is applied to a dual-fuel harbour tug, and the maximum stress of the LNG pipe is significantly decreased by the optimisation of pipe supports. The engineering application example proves that ODMCPSL has high convergence and efficiency.