As the first link element for the transmission of shaft vibration to the pedestal and even to the hull,water-lubricated bearing plays a key role in suppressing vibration.Although the porous structure is considered as ...As the first link element for the transmission of shaft vibration to the pedestal and even to the hull,water-lubricated bearing plays a key role in suppressing vibration.Although the porous structure is considered as one of the main methods for improving the wideband vibration and noise reduction performance of materials in many industrial fields,the studies in the field of water-lubricated bearing remain insufficient.To enhance vibration reduction performance,a fluid-saturated perforated slab is designed in this study,and via the establishment of a fluid-solid coupled vibration model,the influence law and impact levels were analyzed and verified by simulation and experiments.The results obtained verified that the total vibration amplitude of damping-enhanced stern bearing in the vertical direction was smaller than that of the normal stern bearing,and the reduction amplitude of the characteristic frequency agreed with the optimal value at approximately 0.1 of the volume fraction of the liquid phase when the solid-fluid phase was rubber–water.Additionally,the increase in fluid fraction did not enhance the damping effect,instead,it unexpectedly reduced the natural frequency of the raw material significantly.This research indicates that the design of the fluid-saturated perforated slab is effective in reducing the transmission of the vibration amplitude from the shaft,and presents the best volume fraction of the liquid phase.展开更多
This study addresses the lubrication challenges posed by oil-water mixtures that arise when vessels encounter adverse maritime conditions,including collisions,grounding,and reefing,which can lead to failures in lubric...This study addresses the lubrication challenges posed by oil-water mixtures that arise when vessels encounter adverse maritime conditions,including collisions,grounding,and reefing,which can lead to failures in lubrication systems during navigation.The research focuses on three representative ship tail-bearing composites:polymer material(K4),thordon material(SR),and tenmat material(FR).Various volume fractions of oil-water mixtures were prepared,and the rheological properties of these mixtures were examined using a rotational rheometer(MCR102).Additionally,the variation of friction coefficients of the composites about load and linear velocity under different oil-water mixtures was analyzed using a Ring-Block Friction and Wear Testing Machine.Following the experiments,the surface morphology of the composites was assessed,and the wear mechanisms were analyzed using a laser interferometric surface profiler(LI-type),a confocal laser microscope(CLSM),and a scanning electron microscope(SEM).The findings indicate that,under all lubrication conditions,the friction coefficients of the three materials exhibit a gradual decrease with increasing load and linear velocity.Furthermore,the wear of the materials initially increases and then decreases with rising oil content,with higher oil concentrations in the oil-water mixture correlating with reduced wear.The study reveals that the three materials experience significant abrasive and adhesive wear under adverse oil-water mixing conditions.This research offers valuable insights for developing friction substitutes for oil-water mixing bearings in specialized operational environments and guides the design of friction components in such bearings.展开更多
基金Supported by State Key Program Grant of National Natural Science Foundation of China(Grant No.51579198)Key Laboratory of High Performance Ship Technology Opening Foundation(Grant No.2016gxnc04).
文摘As the first link element for the transmission of shaft vibration to the pedestal and even to the hull,water-lubricated bearing plays a key role in suppressing vibration.Although the porous structure is considered as one of the main methods for improving the wideband vibration and noise reduction performance of materials in many industrial fields,the studies in the field of water-lubricated bearing remain insufficient.To enhance vibration reduction performance,a fluid-saturated perforated slab is designed in this study,and via the establishment of a fluid-solid coupled vibration model,the influence law and impact levels were analyzed and verified by simulation and experiments.The results obtained verified that the total vibration amplitude of damping-enhanced stern bearing in the vertical direction was smaller than that of the normal stern bearing,and the reduction amplitude of the characteristic frequency agreed with the optimal value at approximately 0.1 of the volume fraction of the liquid phase when the solid-fluid phase was rubber–water.Additionally,the increase in fluid fraction did not enhance the damping effect,instead,it unexpectedly reduced the natural frequency of the raw material significantly.This research indicates that the design of the fluid-saturated perforated slab is effective in reducing the transmission of the vibration amplitude from the shaft,and presents the best volume fraction of the liquid phase.
基金supported by the National Natural Science Foundation of China(U2341284,51579198)the Postdoctoral Fellowship Program of CPSF under Grant Number GZB20240584the Fundamental Research Funds for the Central Universities(WUT:3120624441).
文摘This study addresses the lubrication challenges posed by oil-water mixtures that arise when vessels encounter adverse maritime conditions,including collisions,grounding,and reefing,which can lead to failures in lubrication systems during navigation.The research focuses on three representative ship tail-bearing composites:polymer material(K4),thordon material(SR),and tenmat material(FR).Various volume fractions of oil-water mixtures were prepared,and the rheological properties of these mixtures were examined using a rotational rheometer(MCR102).Additionally,the variation of friction coefficients of the composites about load and linear velocity under different oil-water mixtures was analyzed using a Ring-Block Friction and Wear Testing Machine.Following the experiments,the surface morphology of the composites was assessed,and the wear mechanisms were analyzed using a laser interferometric surface profiler(LI-type),a confocal laser microscope(CLSM),and a scanning electron microscope(SEM).The findings indicate that,under all lubrication conditions,the friction coefficients of the three materials exhibit a gradual decrease with increasing load and linear velocity.Furthermore,the wear of the materials initially increases and then decreases with rising oil content,with higher oil concentrations in the oil-water mixture correlating with reduced wear.The study reveals that the three materials experience significant abrasive and adhesive wear under adverse oil-water mixing conditions.This research offers valuable insights for developing friction substitutes for oil-water mixing bearings in specialized operational environments and guides the design of friction components in such bearings.
