Develop a standard for the dynamic performance testing and evaluation of existing and future synthetic material suitable for operating in various environmental conditions with propulsion system types. The standard would define the appropriate test requirements to allow direct comparison for guidance in determining what properties will produce the best results for a given application. Guidance will be provided on material properties for bearing and shaft journal (sleeve) surfaces. Environmental and operational conditions include: abrasive waters vs. blue water, constant shaft rpm vs. variable vs. variable with frequent stops and starts. The following list the performance tests that will be defined in the specification. In some instances more than one type of test will be identified to insure that the proper test for the material type is provided. This test will be designed to take into account shaft size, rotational speed, loading, and bearing design. Material Wear Material Stiffness Material Roughness Coefficient of Friction (static and dynamic) Stick-Slip Water Swell Thermal Expansion
There is a need for the creation of a commercial water lubricated main propulsion bearing specification. Currently, the majority of bearing systems are designed by indentifying the best or at least an adequate component on a component-by-component basis. This approach may result in a non-optimal system being designed and constructed. Water lubricated systems work in a way that results in extreme interaction between the bearing material, the shaft sleeve material, and the operating environment. Proper selection of these systems components can have significant impact on commercial vessels by potentially extending the periodicity of dry docking. Currently, there is no standard available for evaluation testing to provide an unbiased material analysis. This is leaves the ship designers and builders to rely on the advice of the bearing venders themselves. By creating a standard to define the test requirements for these systems, the commercial industry has the possibility to dramatically reduce costs and maintenance by designing a water lubricated bearing system that is specifically targeted for their operating profile.
KeywordsPropulsion shaft bearings,
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development