scholarly journals Forensic Engineering Analysis of a Wheel Spindle Failure Due to Pre-Load and Fatigue

Author(s):  
David Danaher

Typically, most vehicles equipped with non-powered wheels use a spindle that not only supports the weight of the vehicle but also allows the rotation of the tire. The rotation of the hub and wheel on the spindle is accomplished with the use of either a tapered or double row ball bearing. Bearings are mounted between the spindle and hub/wheel assembly, then secured with a castle nut set to a specified torque. Tapered bearings are chosen for this application because they are designed for applications where forces are generated radially (vertically) and axially (laterally) during use. Although tapered bearings are ideally suited for use in wheel and spindle assemblies, they must be installed properly to perform as designed. As part of that installation, the spindle nut must be properly torqued in order to apply a sufficient pre-load to the tapered bearings. Without the proper pre-load, the bearings can either generate too much friction or ride improperly on the spindle, generating forces that are not properly distributed. This paper will discuss the failure of a spindle and wheel assembly that experienced fatigue due to improper pre-load of the spindle nut.

Author(s):  
D.S. Sax Saxena ◽  
Saxena Anu

The Influence Of Construction And Pile Driving Vibrations On Surrounding Buildings, Including Hospitals And Eye Examination Facilities, Sensitive Devices Such As Computers And Surgical Microscopes Or Electronic Machines, And People In The Urban Environment Is A Significant Consideration In Obtaining Project Approvals From Appropriate Agencies And Authorities. Implementation Of Construction Projects In Areas Adjacent To Existing Buildings (Aged, Historical, Residential, Commercial, Industrial, Medical Services, Or Electronic Services) Creates Additional Difficulties. Specialized Case History Is Presented Where Damage To Sensitive Structures From A Variety Of Vibratory Construction Methods Ranging From Pile Driving, Highway Construction, Rock Excavation And/Or Blasting, Was Considered. Twenty Homeowners From A Residential Subdivision In The Florida Panhandle, Claimed Damage Including Cracking To Their Properties During Construction Of Various Portions Of City Storm Water Treatment/Enhancement Project. It Was Also Alleged That During Excavation And Construction Of Drainage Structures, Especially Four Subsurface Treatment Vaults That Required Installation And Extraction Of Sheet Piles Using Vibratory Hammer, Stability Of The Nearby Residential Structures Was Endangered And Resulted In Movement/Cracking. Forensic Engineering Analysis Was Effectively Utilized To Identify, Investigate, And Remediate The Concerns As Well As Assist In Litigation And In Some Cases Avoidance. This Technical Paper Presents Some Legal Issues Related To Litigation, Mediation, And Resolution Involving Jurisprudence System And Introduces A Case History That Includes All Elements Of Forensic Engineering.


Author(s):  
Curtis E. Falany

Lightning Is A Powerful And Dangerous Natural Force. It Is Capable Of Inflicting Significant Damage To Our Environment And Causing Injury Or Death In Living Organisms. Electrical And Electronic Circuits Are Particularly Susceptible To Lightning, Both From Direct Strikes And From Lightning Induced Electrical Surges. Fires Often Result From Lightning Strikes. Injury And Death Can Result From Both Direct Strikes, Lightning Induced Electrical Surges, And Indirectly From Structure Damage And Fires. The Insurance In-Dustry Offers Coverage For Lighting Related Losses And A Forensic Engineer Is Often Consulted To Assist In Adjusting The Claim.


Author(s):  
Michael Kravitz

This paper examines the effect of a pedestrian inadvertently impacting a glass panel adjacent to a glass exit door. The glass panel was full length and unmarked, violating the local building code and building commissioner directives. The defense argued that the old building code, to which the college building was constructed, was “grandfathered” and there was no violation. Initial witness and plaintiff statements indicated that the plaintiff was running when he struck the panel, which shattered and caused the plaintiff to incur injuries. The plaintiff testified later, in deposition, that he was walking when he struck the glass. The court needed to establish liability percentage, which is common in civil cases, and it was necessary to determine at what pedestrian impact speed the glass panel would break. The analysis used Timoshenko’s theory of vibration plates, Roark’s stress strain formulas, ergonomics, and human factors to estimate the impact load and stresses on the glass panel that caused failure.


Author(s):  
Jerry R. Tindal

On May 7, 2009 a catastrophic explosion occurred at a shopping mall located just outside of Washington, D.C. As a result of the explosion, several persons, including multiple firefighters, were injured, and a large portion of the mall was destroyed. This paper examines the cause of the explosion.


Author(s):  
John Leffler

A forensic case involved an allegation of defective minivan brake repairs. On a wet two-lane road, the minivan left the road while stopping, and impacted a telephone pole. The plaintiff driver’s complaints implied a dragging brake, and the plaintiff ’s expert reported a bent lower caliper bolt. This forensic investigation involved instrumented exemplar analysis of the effects on caliper drag that could be caused by a bent caliper bolt. The investigation methodology was chosen (in part) based on significant evidence spoliation on the part of the plaintiff ’s expert. This paper will also discuss the effects of the spoliation and resulting limitations on the scope of the analysis.


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