scholarly journals Forensic Engineering Analysis Of Failed Roller Bearings

1998 ◽  
Vol 15 (2) ◽  
Author(s):  
Olof H. Jacobson
Keyword(s):  
Case Studies ◽  
Forensic Analysis ◽  
Rolling Contact ◽  
Rolling Element Bearings ◽  
Bearing Failure ◽  
Engineering Analysis ◽  
Operating Characteristics ◽  
Bearing Failures ◽  
Rolling Element ◽  
Forensic Engineering

Failure Of Rolling Element Bearings Often Results In Damage To The Bearing Elements And Adjacent Components Such As Axles, Shafts, Gearboxes, Wheels, Etc. Forensic Analysis Of Rolling Contact Bearings Is Discussed In This Paper. A Review Of Bearing Types And Typical Operating Characteristics Is Presented. A Procedure For Systematic Examination And Analysis Of Bearing Failure Evidence Is Suggested, And Several Case Studies Are Presented Which Demonstrate The Types Of Evidence Typically Remaining And The Logic Which Leads To Engineering Conclusions Concerning The Cause Of Bearing Failures.

Analysis of the conditions for the occurrence of the effect of a minimum of friction in hybrid bearings based on the load separation principle

2018 ◽  
Vol 233 (2) ◽  
pp. 271-280
Author(s):  
Roman Polyakov ◽  
Leonid Savin ◽  
Alex Fetisov
Keyword(s):  
Rolling Contact ◽  
Friction Reduction ◽  
Fluid Film ◽  
Rolling Element Bearing ◽  
Contact Friction ◽  
Rolling Element Bearings ◽  
Operating Characteristics ◽  
Fluid Film Bearings ◽  
Friction Regime ◽  
Rolling Element

Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotational speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary operating characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. A hybrid bearing, where a rolling-element bearing and a fluid-film bearing are positioned parallel to the vector of external load (PLEX), has the following advantages compared to a single bearing, whether rolling-element or fluid-film one: increase of life expectancy, load capacity increase, friction reduction, thermal regime enhancement, increase of stiffness, and damping properties. The present paper presents the results of theoretical and numerical research of friction characteristics of PLEX in mixed sliding and rolling friction, i.e. combination of viscous and rolling contact friction, regime. The conditions of minimum friction effect occurrence have been substantiated, and rational relations between characteristics of hybrid rolling-element bearings and fluid-film bearings needed for provision of such effect have been experimentally proven. Finally, the paper presents recommendations regarding design of such hybrid bearings for heavily loaded bearing nodes of rolling mills.

scholarly journals Forensic Engineering Analysis of a Fatal Trailer Wheel-Separation Failure

2017 ◽  
Vol 34 (2) ◽  
Author(s):  
Stephen A. Batzer
Keyword(s):  
Forensic Analysis ◽  
Front Wheel ◽  
Engineering Analysis ◽  
Passenger Compartment ◽  
Traffic Lane ◽  
Forensic Engineering ◽  
Cantilever Bending ◽  
Winter Time ◽  
Separation Failure ◽  
Left Front

A forensic analysis of a fatal trailer wheel-separation failure is presented in this paper. An older three-axle trailer carrying snowmobiles was being driven at highway speed during winter time in Michigan. The left front wheel detached due to the catastrophic failure of all six lug studs. The wheel traveled into the on-coming traffic lane and struck the roof of a sedan driven by a local student. The driver of this vehicle was killed instantly due to passenger compartment intrusion. One possibility was that the lug nuts were improp-erly tightened during a recently performed service — and that this looseness diminished clamping forces and led to cantilever bending of the studs and fatigue fracture. An analysis of the defendant’s narrative and of the failure were performed.

scholarly journals Further understanding of rolling contact fatigue in rolling element bearings - A review

2019 ◽  
Vol 140 ◽  
pp. 105849 ◽  
Author(s):  
Mostafa El Laithy ◽  
Ling Wang ◽  
Terry J. Harvey ◽  
Bernd Vierneusel ◽  
Martin Correns ◽  
...  
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Rolling Element Bearings ◽  
Rolling Element

Rolling Element Bearing Monitoring and Diagnostics Techniques

1989 ◽  
Vol 111 (2) ◽  
pp. 251-256 ◽  
Author(s):  
R. G. Harker ◽  
J. L. Sandy
Keyword(s):  
Case Studies ◽  
Fluid Film ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Film Type ◽  
Rolling Element ◽  
Element Bearing ◽  
Monitoring And Diagnostics ◽  
Bearing Monitoring

Rolling element bearings require distinctly different techniques for monitoring and diagnostics from those used for fluid-film type bearings. A description of these techniques and the instrumentation used to acquire the necessary data is provided for comparison. Also included are some case studies to illustrate how these techniques are applied.

Diagnosis of Rolling-Element Bearings Failure by Localized Electrical Current Between Track Surfaces of Races and Rolling-Elements

2002 ◽  
Vol 124 (3) ◽  
pp. 468-473 ◽  
Author(s):  
Har Prashad
Keyword(s):  
Theoretical Model ◽  
Electrical Current ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Bearing Failure ◽  
Cause Analysis ◽  
Rolling Element ◽  
Rolling Elements ◽  
Dimensional Parameters ◽  
Element Bearing

The diagnosis and cause analysis of rolling-element bearing failure have been well studied and established in literature. Failure of bearings due to unforeseen causes were reported as: puncturing of bearings insulation; grease deterioration; grease pipe contacting the motor base frame; unshielded instrumentation cable; the bearing operating under the influence of magnetic flux, etc. These causes lead to the passage of electric current through the bearings of motors and alternators and deteriorate them in due course. But, bearing failure due to localized electrical current between track surfaces of races and rolling-elements has not been hitherto diagnosed and analyzed. This paper reports the cause of generation of localized current in presence of shaft voltage. Also, it brings out the developed theoretical model to determine the value of localized current density depending on dimensional parameters, shaft voltage, contact resistance, frequency of rotation of shaft and rolling-elements of a bearing. Furthermore, failure caused by flow of localized current has been experimentally investigated.

scholarly journals Forensic Analysis Of Tilting File Cabinets

2002 ◽  
Vol 19 (2) ◽  
Author(s):  
Wilbur T. Yaxley
Keyword(s):  
Forensic Analysis ◽  
Engineering Analysis ◽  
Back Injuries ◽  
Forensic Engineering ◽  
File Cabinet

This Case Involved A File Clerk Inserting Files Into An Office 4 Drawer File Cabinet. The File Cabinet Did Not Have Latching Devices For The Drawers. The File Drawers Were Designed To Be Stabilized With A Small Indent In The Suspension Track To Prevent The Drawers From Unexpectedly Opening. The File Cabinet Unexpectedly Tilted And Opened All The Drawers With A Force Sufficient To Knock The Clerk To The Floor With The File Cabinet On Her Back. The Clerk Sustained Substantial Back Injuries. The Jury Agreed With The Forensic Engineering Analysis And Were Shocked At The Ease Of The Drawers Opening, The Cabinet Falling, And The Force Of Overturning Of The File Cabinet. The Jury Awarded The Verdict To The Plaintiff With A Surprising Twist.

The Condition Monitoring of Rolling Element Bearings Using Vibration Analysis

1984 ◽  
Vol 106 (3) ◽  
pp. 447-453 ◽  
Author(s):  
J. Mathew ◽  
R. J. Alfredson
Keyword(s):  
Condition Monitoring ◽  
Sufficient Evidence ◽  
Rolling Element Bearings ◽  
Bearing Failure ◽  
Machine Condition ◽  
Vibration Data ◽  
Machine Condition Monitoring ◽  
Rolling Element ◽  
Vibration Signatures ◽  
Bearing Damage

A brief review on techniques of machine condition monitoring is presented followed by a description and results of a study involving the monitoring of vibration signatures of several rolling element bearings with a view to detecting incipient failure. The vibration data were analyzed and several parameters were assessed with regard to their effectiveness in the detection of bearing condition. It was found that all the parameters were of some value depending on the type of bearing failure encountered. Generally, frequency domain parameters were more consistent in the detection of damage than time domain parameters. However, sufficient evidence is produced to show that it would be unreliable to depend exclusively on any one technique to detect bearing damage.

scholarly journals Forensic Engineering Analysis Of Workplace Exposure To Airborne Contaminants

2000 ◽  
Vol 17 (2) ◽  
Author(s):  
Drew Peake
Keyword(s):  
Case Studies ◽  
Common Element ◽  
Engineering Analysis ◽  
Workplace Exposure ◽  
Airborne Contaminants ◽  
Forensic Engineering ◽  
The Common ◽  
Technical Basis

This Forensic Engineering Analysis Of Workplace Exposure To Airborne Contaminants Presents Three Case Studies. The Common Element Is That Each Responds To The Generalized Complaint That A Contaminant Is Presumed Present And Therefore Presumed To Cause Harm. The First Discusses Conditions That An Auto Mechanic Was Exposed To While Replacing Asbestos Containing Brake Linings. The Second Responds To Diagnosed Disease Resulting From Exposure To Bioaerosols. The Final Case Regards Landlord Concerns That Airborne Contaminants From A Printing Operation May Contaminate The Property. The Technical Basis For Responding To These Complaints Is Presented.

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