Numerical Stress Analysis of Sandwich Cryogenic Pipeline

Liquefied natural gas (LNG) pipeline is often built on top of trestle system to transport it from liquefaction plant to LNG vessel. However, the use a vessel is very expensive for long term operation, which led to the development of subsea sandwich cryogenic pipeline. Although the new pipeline can resist the cryogenic temperature, its performance in terms of strength is yet to be tested under deep water situation. Therefore, this research aim to determine the strength of the sandwich cryogenic pipeline in terms of stress, strain, deformation, safety factor, and heat flux using ANSYS as finite element modelling software. The results were compared using three different materials, which are stainless steel, 36% nickel (Invar), and the proposed 29% nickel (Kovar). The results showed that, in term of overall performance, Kovar performed better in terms of stress, strain, deformation, and safety factor. However, in terms of heat flux, Invar performed better than Kovar. To improve the reliability of this research, further modification is suggested by conducting fatigue and stability test in the analysis.