Simulations and Measurements of the Vibroacoustic Effects of Replacing Rolling Element Bearings With Journal Bearings in a Simple Gearbox

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Stephen A. Hambric ◽  
Micah R. Shepherd ◽  
Robert L. Campbell ◽  
Amanda D. Hanford
Keyword(s):  
Finite Element Analysis ◽  
Journal Bearings ◽  
Component Mode Synthesis ◽  
Rolling Element Bearings ◽  
Element Analysis ◽  
Free Boundary Conditions ◽  
Damping Coefficients ◽  
Rolling Element ◽  
Gearbox Vibration ◽  
Solution Methods

The effects of replacing rolling element bearings with journal bearings on the noise and vibration of a simple gearbox are computationally and experimentally evaluated. A modified component mode synthesis (CMS) approach is used, where the component modes of the shafting and gearbox housing are modeled using finite element analysis (FEA). Instead of using component modes with free boundary conditions, which is typical of CMS, the shafting and gearbox are coupled using nominal impedances computed for the different bearing types, improving convergence of the solution. Methods for computing the actual bearing impedances, including the high damping coefficients in journal bearings, are summarized. The sound radiated by the gearbox is computed using a boundary element (BE) model. The modeling results are validated against measurements made at the NASA Glenn Research Center. Both simulations and measurements reveal that the journal bearings, although highly damped, do not necessarily lead to strong reductions in gearbox vibration and noise.

Simultaneous Monitoring of Rolling-Element and Journal Bearings Using Analysis of Structure-Born Ultrasound Acoustic Emissions

2010 ◽  
Author(s):  
A. Albers ◽  
M. Dickerhof
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emissions ◽  
Piezoelectric Sensor ◽  
Journal Bearings ◽  
Rolling Element Bearings ◽  
Acoustic Emission Sensor ◽  
Outer Race ◽  
Rolling Element ◽  
Characteristic Values ◽  
Acoustic Emission Technology

The application of Acoustic Emission technology for monitoring rolling element or hydrodynamic plain bearings has been addressed by several authors in former times. Most of these investigations took place under idealized conditions, to allow the concentration on one single source of emission, typically recorded by means of a piezoelectric sensor. This can be achieved by either eliminating other sources in advance or taking measures to shield them out (e. g. by placing the acoustic emission sensor very close to the source of interest), so that in consequence only one source of structure-born sound is present in the signal. With a practical orientation this is often not possible. In point of fact, a multitude of potential sources of emission can be worth considering, unfortunately superimposing one another. The investigations reported in this paper are therefore focused on the simultaneous monitoring of both bearing types mentioned above. Only one piezoelectric acoustic emission sensor is utilized, which is placed rather far away from the monitored bearings. By derivation of characteristic values from the sensor signal, different simulated defects can be detected reliably: seeded defects in the inner and outer race of rolling element bearings as well as the occurrence of mixed friction in the sliding surface bearing due to interrupted lubricant inflow.

Some Effects of Lubricant Composition and Tappet Rotation on Cam/Tappet Friction

1989 ◽  
Vol 111 (4) ◽  
pp. 683-691 ◽  
Author(s):  
P. A. Willermet ◽  
J. Pieprzak
Keyword(s):  
Experimental Data ◽  
Frictional Contact ◽  
Angular Resolution ◽  
Friction Model ◽  
Journal Bearings ◽  
Valve Train ◽  
Wave Form ◽  
Rolling Element Bearings ◽  
Lubricant Composition ◽  
Rolling Element

A cam/tappet friction rig was constructed from a 1.6 L Ford valve train. The head casting and the camshaft were shortened so that only two journal bearings remained. Only one of the two remaining cam/tappet contacts was used as a frictional contact. All other contacts were equipped with rolling element bearings so that essentially all the turning torque came from cam/tappet friction and valve spring forces. The rig, together with a data acquisition/wave form analyzer system and a computer, was capable of measuring instantaneous torque with an angular resolution of less than one degree, and reducing the data to provide calculated values for parameters such as the friction coefficient. The experimental data were compared with results from a cam/tappet friction model to assist in interpretation. The data and model illustrated that lubricant composition and tappet rotation have important effects not only on overall friction, but also on the shape of friction versus cam angle curves.

Numerical Simulation of Transient Finite Deformations of Thin Beams

1983 ◽  
Vol 50 (4a) ◽  
pp. 765-769
Author(s):  
J. J. A. Rodal ◽  
D. J. Steigmann ◽  
E. A. Witmer
Keyword(s):  
Numerical Simulation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Deformations ◽  
Viscoplastic Deformation ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Solution Methods ◽  
Representative Problem ◽  
Thin Beams

The formulation of the problem of finite elastic-viscoplastic deformation of thin beams is described. The finite element analysis of a representative problem is presented and various solution methods are surveyed.

Influence of the bolt size on the source of damping in automotive joints

2021 ◽  
Vol 263 (3) ◽  
pp. 3424-3435
Author(s):  
Shaan Sanjeev ◽  
Dan J. O'Boy ◽  
Paul Cunningham ◽  
Steve Fisher
Keyword(s):  
Finite Element Analysis ◽  
Experimental Investigation ◽  
Experimental Tests ◽  
Lap Joints ◽  
Bolted Joints ◽  
Controlled Experiments ◽  
Element Analysis ◽  
Free Boundary Conditions ◽  
Single Lap Joints ◽  
Forced Excitation

Experimental tests are carried out on automotive bolted joints to study the influence of the bolt size on the source of damping during dynamic loading. Aluminium beams and five different bolt sizes are chosen and used to assemble single-lap joints under strictly controlled experiments. Measurements are taken to estimate the energy loss during forced excitation and to identify the source of damping in jointed structures, and an analogous monolithic solid beam is also used during the experimental investigation to isolate the joint effects and compare the data gathered. The dynamic response of the jointed structure exposed to forced excitation is captured under free-free boundary conditions. The motion of the assembled structure is identified by carrying out a finite element analysis.

Finite Element Analysis of Dynamically Loaded Flexible Journal Bearings: A Fast Newton-Raphson Method

1989 ◽  
Vol 111 (4) ◽  
pp. 597-604 ◽  
Author(s):  
J. D. C. McIvor ◽  
D. N. Fenner
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Computing Time ◽  
Journal Bearings ◽  
Element Analysis ◽  
Dynamically Loaded ◽  
Newton Raphson ◽  
Time Required ◽  
Raphson Method ◽  
Isoparametric Elements

A fast Newton-Raphson method is presented for the finite element analysis of dynamically loaded flexible journal bearings. The method makes use of 8-node isoparametric elements for the lubrication analysis and 20-node isoparametric elements for the structural analysis. Results are presented for the Ruston and Hornsby 6VEB Mk III marine diesel big-end bearing using this method. The computing time required for this analysis is more than two orders of magnitude less than that previously reported for an elastohydrodynamic bearing analysis using a conventional Newton-Raphson method.

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