Session: 03-16-01: Manufacturing: General

Paper Number: 112998

112998 - Mechanical Analysis of an Additive Manufactured Deflecting-Tapered-Land Hydrodynamic Thrust Bearing 

Unlike traditional thrust bearings that rely on balls or rollers to reduce friction between rotating and axially loaded components, hydrodynamic bearings utilize lubricants to reduce friction. A common type of hydrodynamic thrust bearing is the tapered-land bearing. A siphoning action occurs during operation due to relative convergence and rotation of the components which force lubricant into the tapered geometry of the bearing thus creating a thin film. The lubricant film becomes pressurized as it is forced into the tapered zone; this pressurized film separates and supports the rotating and axially loaded components thus producing low operational frictional coefficients. The height of the taper is predetermined before manufacturing and is governed by expected operating conditions such as rotational speeds, axial loads, or lubricant viscosity. If operating conditions occur outside of the predetermined specifications, the bearing will operate with increased friction coefficients or decreased load capacities which may result in damage to the system in which they were installed. Traditionally, tapered-land hydrodynamic bearings are produced using subtractive manufacturing techniques. The major bearing geometry, including the tapered portions, are machined from stock material using computer numerically controlled lathes or mills. Additive manufacturing contrasts with subtractive manufacturing such that the final product can be built using a bottom-up or layer-by-layer technique; these types of manufacturing techniques can also produce final products with embedded features which otherwise could not be produced using traditional subtractive techniques. Examples of additive manufacturing techniques include fused filament fabrication, composite layup or winding, and powder bed fusion. Both fused composite filament fabrication and composite layup manufacturing have demonstrated in literature to be a viable production method to reduce manufacturing costs and expand operational capacities for tapered-land hydrodynamic bearings. Typically, fused filament fabrication and composite layups are composed mostly of polymer materials as the main constituent which may result in decrease wear and fatigue resistance when used for bearing materials. Powder bed fusion utilize metals during manufacturing which have increased wear and fatigue resistance when compared to polymer-based materials. The research presented here aims to expand upon additive manufacturing in the hydrodynamic bearing industry. Unlike previous research which simulated the use of polymer composite materials to omit subtractive manufacturing of the bearing geometry, the research presented here investigates the use of metal powder bed fusion manufacturing of tapered-land hydrodynamic bearings to create a self-governing bearing which deflects during applied loading and oil film pressure generation; this deflecting action provides a self-adjustment in taper height which aids in oil film production and load capacity extension. Experimental analysis was conducted on powder bed fusion fabricated aluminum samples to obtain the thermal expansion coefficient, Poisson’s ratio, and Young’s modulus of the samples. Thermo-mechanical analysis was then conducted in Abaqus/Standard to show deflection magnitudes of the tapered sections of the bearing in relation to oil film pressures. The data obtained in this analysis provides evidence that powder bed fusion fabrication can be used to reduce manufacturing cost and expand operating capabilities of hydrodynamic bearings.

Presenting Author: Muhammad Ali Ohio University

Presenting Author Biography: Neil D Thomas Professor, CAMP Director, and Graduate Chair of Mechanical Engineering

Authors:

Isaiah Yasko Ohio University
William Downs Ohio Univeristy
Collier Fais Ohio University
Muhammad Ali Ohio University
Brian Wisner Ohio University
Rick Walker Miba Bearings