Experimental study on intra-ply shear and inter-ply sliding behaviors in cryogenic composite hoses

Abstract

Cryogenic composite hose is the key equipment for tandem offloading operation of Floating Liquefied Natural Gas (FLNG). During the tandem offloading, the harsh marine environment results in hulls motion responses and complex hose motion characteristics. And the interlayer mechanical properties of the hose are easily affected by the external environment. In this paper, the interlayer behavior under different conditions (cryogenic temperature, dry-wet condition, and normal pressure) were investigated. The results showed that the low temperatures had little effect on the shear and sliding properties, resulting from little effect on the surface friction behaviors of the tows under low-temperature environment. Besides, sliding behavior was more likely to occur in wet condition, which was mainly derived from the presence of a water film between the layers, thus reducing the coefficient of friction (COF). Additionally, the COF decreased first and then reached minimum value followed by a plateau with the increasing of the normal force. Considering the effects of the intra-ply shear behaviors of fabric and normal pressure, a friction model coupling shear and sliding behavior was proposed, which fitted well with the experimental data and provides a reference for future structural design, numerical simulation and life prediction of cryogenic composite hoses.