Development of a friction test apparatus for simulating the ultra-high pressure environment of the deep ocean

Abstract

The continued development of deep-ocean equipment requires improved friction and wear resistance of key tribopairs in a high pressure environment. However, there is little research on the effect of high hydrostatic pressure on the tribological properties of different tribopairs as available test rigs are scarce. In this work, a friction test apparatus was developed to help carry out this research. A non-contact gap seal and uniquely shaped loading system were developed to adapt to the high pressure environment and improve measurement accuracy. The fatigue life simulation of key components was conducted to ensure the safety and reliability of the apparatus. Pilot studies on tribopairs consisting of 30 vol% carbon fiber-reinforced polyetheretherketone (CFRPEEK) and AISI 431 stainless steel (431SS) lubricated with high-pressure water were conducted. The results indicated that the apparatus could work stably under an ultra-high hydrostatic pressure of 80 MPa. Friction was found to decrease with increasing hydrostatic pressure. Maximum wear of CFRPEEK occurred at 20 MPa. The results also showed that the CFRPEEK/431SS tribopair could be used in the deep ocean at depths of less than 8000 m as the friction and wear of the tribopair did not degenerate sharply for pressures of 0–80 MPa.