Effect of Microtexture Arrangement on Tribological Properties of Water-lubricated Bearings During Start-stop Process
Water-lubricated bearings are key components of the trailing axis systems of naval equipment and are widely used in ship axis systems.Bearings are often subjected to unbalanced forces,such as inertial forces caused by the weight of the propeller and additional forces generated by the deformation of the vessel body during its operation.These harsh working conditions would result in poor lubrication of the bearings and cause severe friction and wear.The gradient-arranged microtexture has a significant effect on improving the tribological performance of water-lubricated bearings,which is significant for improving the bearing lubrication and load-bearing performance and reducing wear.However,systematic research on the application of gradient-arranged microtextures in water-lubricated bearings is lacking.To evaluate the effect of the gradient-arranged texture on the tribological performance of water-lubricated bearings during the start-stop process,the surface wear of the shaft shank is solved based on the Greenwood-Tripp micro-convex body contact model and the Archard wear model.The effect of the microtextured arrangement on the tribological performance of the water-lubricated bearings during the start-stop process is analyzed.The tribological properties of water-lubricated gradient-arranged textured surfaces are evaluated using the CFT-I material surface property comprehensive tester,which verifies the results of the numerical calculations.The gradient-arranged textured surfaces are manufactured by the computer numerical control engraving machine.The effects of the microtextured depth and circumferential spacing on the average wear of water-lubricated bearing surfaces are calculated using numerical simulations.The optimal microtextured depth and circumferential spacing are selected to design the microtextured arrangement based on the numerical simulation results.The effects of the microtexture gradient-arranged on the average wear of the water-lubricated bearing surfaces are also calculated.The wear amounts and friction factors of each surface are measured for the smooth,single-circular texture,circular and triangular surfaces arranged in a gradient of axially staggered parallel(112),and circumferentially staggered parallel distribution(1212).The morphology and friction factor of the surfaces before and after the frictional wear experiments are analyzed using stereo microscopy and scanning electron microscopy.The effects of the gradient-arranged microtexture on the surface morphology and friction factor of the water-lubricated bearings are analyzed.The numerical simulation results showed that the surface wear amounts of the gradient-arranged microtexture were significantly decreased compared with those of the smooth and single-texture surfaces.The best tribological performance of the gradient-arranged microtextured surfaces with the circular composite triangle in the form of 112 had the lowest wear amount at the contact surface.The experimental results showed that the friction factor of the gradient-arranged microtextured surfaces was more than 40％lower than that of smooth and single-textured surfaces.Similarly,the surface with circular composite triangles arranged in the form of an[2 gradient microtexture had the lowest friction factor.There were evident water film pressure convergence zones on the bearing surface under water-lubricated conditions,which could enhance the water film lifting force and generate dynamic pressure effect.The gradient-arranged microtextures interact with each other in the fluid lubrication process to enhance the lifting force on the bearing surface,which plays a role in reducing the surface wear and lowering the friction factor of the contact surface.Thus,an appropriate gradient-arranged microtexture can significantly improve the tribological performance of bearing surfaces.Increasing the convergence zone of the surface water film pressure,improving the surface lifting force,and reducing the surface contact,surface friction factor,and surface wear should be considered when designing the surface micro-texture.The study of the influence of different shapes and arrangements of gradient-arranged microtexture-structured surfaces on the wear amount and friction factor can provide a theoretical basis for the active design of water-lubricated bearings in the development stage of naval equipment.
万方数据
维普
