Reliability Assessment of the Water Distributing Valve of a Hydrostatic Sediment Corer

Abstract

The hydrostatic corer is designed for sampling sediment from the seafloor. Its operation relies on a water distributing valve which converts the potential pressure difference between ambient seawater and a built-in chamber with atmospheric pressure to the dynamic energy as the driving power. As the valve is exposed to the ambient water, the deformation of its components may exceed their fitting tolerance under the high pressure and low temperature on seafloor, and thus cause the failure of the valve. Three possible failure modes have been taken into account, representing the positions where interference of fitting tolerance is likely to occur. Corresponding models are then created considering the coupled effects of pressure and temperature on the valve. Based on the model results and the reliability requirement of the corer, one failure mode is selected to calculate the reliability of the valve and is used as guidance for the future improvement of the design.