scholarly journals Forensic Engineering Investigation of Electrical and Electronic Causes of an Industrial Equipment Failure

2022 ◽  
Vol 38 (2) ◽  
Author(s):  
Robert Peruzzi
Keyword(s):  
Electrostatic Discharge ◽  
Equipment Failure ◽  
Industrial Equipment ◽  
Root Cause ◽  
Three Phase ◽  
Forensic Engineering ◽  
Engineering Investigation ◽  
Electrical Contractors ◽  
Random Failures ◽  
Secondary Power

This case involved industrial equipment whose repeated, seemingly random failures resulted in the buyer of that equipment suing the seller. The failures had been isolated to a group of several transistors within electro-mechanical modules within the equipment, but the root cause of those transistors failing had not been determined. The equipment seller had more than 1,000 units in the field with no similar failures. And the electro-mechanical module manufacturer had more than 20,000 units in the field with no similar failures. Electrical contractors hired by the buyer had measured power quality, and reported no faults found in the three-phase power at the equipment terminals. This paper presents circuit analyses of the failing electro-mechanical module, basics of electrostatic discharge damage and protection, and the root cause of these failures — an electrical code-violating extraneous neutral-to-ground bond in a secondary power cabinet.

scholarly journals Forensic Engineering Investigation Of Sectional Ladder Treestand Failures

2013 ◽  
Vol 30 (2) ◽  
Author(s):  
Jahan Rasty
Keyword(s):  
Structural Strength ◽  
Standard Requirement ◽  
Root Cause ◽  
Section Modulus ◽  
Minimum Requirements ◽  
Cause Of Failure ◽  
Forensic Engineering ◽  
Trade Names ◽  
Testing Standards ◽  
Engineering Investigation

The Purpose Of This Forensic Engineering Investigation Was To Determine The Root-Cause Of Failure Of Three 15-Foot Sectional Ladder Treestands That Caused Injury To Users. All Three Treestands Were Identical In Design And Manufactured By The Same Company Despite Differences In Trade Names. Within A Reason-Able Degree Of Scientific And Engineering Certainty, It Was Concluded That Failure Of The Treestands Was The Result Of Overstressing The Star-Crimped Area Of The Treestands At Adjoining Ladder Sections. Overstressing Was Caused By A Designed Reduction In Section Modulus Of The Rail At Adjoining Ladder Sections. Further, The Load-Bearing Ability Of The Ladder Treestands Was Evaluated In Accordance With Com-Monly Accepted Engineering Principles For Metal Ladder Design (Ansi A14.2-2007). Analysis Revealed That The Structural Strength Of The Rail Section And Testing Standards For The Treestand Industry Are Lack-Ing When Compared To Portable Metal Ladders Designed For Identical Load Ratings. In Fact, The Treestands Failed To Meet The Standard Requirement For A Portable Metal Ladder Rated At 170-Pounds Even When The Treestand Was Tested At ½ Of Its Spanning Length (2-Sections). Comparisons Between The Treestands And Portable Metal Ladder Standards Indicated That The Treestands Failed To Meet Minimum And Generally Accepted Standards For Ladder Design And Suggested The Treestands Do Not Meet Minimum Requirements For Merchantability.

scholarly journals Forensic Engineering Investigation into Factors Contributing to Explosion of a Consumer-Grade Tabletop Torch

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Jahan Rasty
Keyword(s):  
Product Design ◽  
Burn Injuries ◽  
Severe Burn ◽  
Root Cause ◽  
Citronella Oil ◽  
Severe Burn Injuries ◽  
Forensic Engineering ◽  
Engineering Investigation ◽  
Perfect Storm

In early 2013, approximately 3,500 consumer-grade tabletop torches, designed for use with citronella oil to ward off insects, were sold by a retailer. Within six months of their debut, 22 of these products experi-enced sudden explosions, resulting in one fatality and 21 severe burn injuries to consumers. The author was retained as an expert in the fatal explosion case to determine the root cause(s) that led to these explosions. This paper will describe the detailed, experimental-based investigation that was carried out to reveal design, manufacturing, and marketing defects for which the designer of the torch, the manufacturer of the fuel, and the retailer of the final product were responsible. It was determined that the explosions occurred as a result of a “perfect storm” scenario that involved defective product design, defective marketing of the product through the sale of incompatible fuel by the retailer, and deficient warning instructions by the manufacturer.

A three-phase sag generator for testing industrial equipment

1996 ◽  
Vol 11 (1) ◽  
pp. 526-532 ◽  
Author(s):  
E.R. Collins ◽  
R.L. Morgan
Keyword(s):  
Industrial Equipment ◽  
Three Phase

scholarly journals Forensic Engineering Investigation Of Failure Of An Oil Pipeline

2012 ◽  
Vol 29 (1) ◽  
Author(s):  
William R. Broz
Keyword(s):  
Contaminated Soil ◽  
Fuel Oil ◽  
Weld Repair ◽  
Butt Weld ◽  
Oil Pipeline ◽  
Weld Joints ◽  
General Contractor ◽  
Forensic Engineering ◽  
Engineering Investigation ◽  
Surrounding Soil

A Below-Grade, Nps 12 Pipeline Serving A Major Commercial Marine Terminal Failed At A Flanged Joint, Causing A Major Leak And Contamination Of The Surrounding Soil. The Gasket At The Failed Joint Showed Evidence Of Localized, Radial Through-Leakage. At The Terminal, The Initial Excavation Of Contaminated Soil Caused Minor Damage To Several Non-Leaking Segments Of Pipe And The Author Was First Tasked To Oversee The Related Inspection, Weld Repair And Corrosion Protection Work. The Author Subsequently Performed A Forensic Pipe Stress Analysis Of The Affected Portion Of The Fuel Oil System Per The Governing Pressure Piping Code. The Results Indicated That The Leaking Joint Failed With Respect To The Code Criterion Of Equivalent Pressure. Further Investigation Revealed That The System As Originally Designed Was Entirely Of Butt Weld Construction With No Flanged Joints, And Would Have Complied With All Code Requirements. The Investigation Determined That The General Contractor Had Made An Unauthorized Substitution Of Flanged Joints For Butt Weld Joints, Without Informing The Owner Or Design Engineer Of Record.

scholarly journals Forensic Engineering Investigation Of Dezincification In A Major Corrosion Litigation

2013 ◽  
Vol 30 (1) ◽  
Author(s):  
Robert N. Anderson
Keyword(s):  
Zinc Content ◽  
Building Code ◽  
Insurance Companies ◽  
Urban Location ◽  
Home Owner ◽  
Plumbing Systems ◽  
Forensic Engineering ◽  
Low Strength ◽  
Engineering Investigation

Zinc-Rich Brasses With The Zinc Content Above 30% Can Be Involved In Corrosion Processes With Catastrophic Results. The Dezincification Results In A Low Strength Copper With A Porous Sponge Like Structure. The Case, Where Dezincification Occurred With Massive Impact, Involved 34,000 New Homes In An Urban Location In Nevada. These Homes Were Constructed Using Building Code Approved Plastic Pex Tubing For Plumbing With Brass Fittings. Leaks Developed In The Home Plumbing Systems After Approximately 3-6 Years. This Failure Resulted In Lawsuits Involving Home Owner Associations, Insurance Companies, Contractors, Plumbers, Architects, Manufacturers, And Suppliers.

scholarly journals Forensic Engineering Investigation of Above-Ground Pool Submersion Accidents

2015 ◽  
Vol 32 (2) ◽  
Author(s):  
Richard Ziernicki ◽  
William H. Pierce
Keyword(s):  
United States ◽  
The United States ◽  
Swimming Pool ◽  
Consumer Product Safety Commission ◽  
Adult Supervision ◽  
Forensic Engineering ◽  
Product Defect ◽  
Engineering Investigation ◽  
Alternative Designs

In the United States, approximately 35 children under the age of five years old drown each year after access-ing above-ground pools via pool ladders. Consumer Product Safety Commission (CPSC) data also shows that approximately 486 additional children sustain submersion-related injuries after accessing above-ground pools via pool ladders. In many cases, these events occurred during brief lapses of adult supervision. This paper fo-cuses on potential product defect issues related to child submersion accidents, including the role of user manuals, alternative designs, warnings, instructions, and child behavior testing. The authors examine the issues related to the investigation of above-ground swimming pool submersion accidents. In addition, procedures and steps are outlined that may be useful in analyzing whether the swimming pool is defective and unreasonably dangerous.

scholarly journals Forensic Engineering Investigation of a Fatal Farm Tractor Incident

2018 ◽  
Vol 35 (2) ◽  
Author(s):  
Daniel P. Couture
Keyword(s):  
Head Injuries ◽  
Field Tests ◽  
Cad Model ◽  
Small Farm ◽  
Sequence Of Events ◽  
Farm Tractor ◽  
Parking Brake ◽  
Forensic Engineering ◽  
Engineering Investigation

A farm owner was found unresponsive with crushing head injuries on his property in rural Ontario. His small farm tractor was found 60 meters away down a small incline with the engine running and transmission in neutral. The owner’s son alleged that when the parking brake was engaged (with the engine running and transmission in neutral), this tractor’s parking brake would “pop out,” allowing the tractor to move. Field tests were conducted on the tractor to attempt to duplicate the scenario and to determine if the alleged sequence of events was plausible. Components of the parking brake and one exemplar were assessed with specialized metrology to determine whether they were within the manufacturing specifications on the blueprint. A 3-D CAD model of fit was created, and several variances were identified between the parts and the factory drawing. The results of the analysis concurred with the scenario that these variances led to the disengagement of the parking brake and operator fatality.

scholarly journals A Forensic Engineering Investigation Of a Ladder Failure

2009 ◽  
Vol 26 (2) ◽  
Author(s):  
Nicholas A. Petrucci
Keyword(s):  
Load Capacity ◽  
National Standards ◽  
Shear Load ◽  
Improper Use ◽  
Forensic Engineering ◽  
Left Front ◽  
Engineering Investigation

A Worker (Plaintiff) Fell From A Step-Ladder And Was Injured. The Purpose Of The Forensic Engineering Investigation Was To Determine The Cause(S) Of The Incident, And In Particular, If The Incident Was Caused By A Ladder Defect. The Incident Ladder And A Representative Incident Scene Were Inspected. Various Discovery Documents And The Applicable American National Standards Institute (Ansi) Standard Were Reviewed. A Critique From The Opposing (Defendant) Expert Is Presented And Addressed. The Cause Of The Plaintiff Fall From The Ladder Was Determined To Be Its Sudden Instability Due To The Failure Of A Rivet That Secured The Top Cap To The Left-Front Rail. The Failed Rivet Was Not Recovered. Further Analysis Indicated That The Cause Of The Rivet Failure Was Its Defective Design Coupled With Its Reduction In Shear Load Capacity From Normal And Improper Use Of The Ladder. The Determination Of The Defective Design Of The Rivet Was Confirmed By Subsequent Design Improvements Of The Ladder. The Relevance Of The Analysis Performed Is Discussed. Various Noteworthy Points Are Presented For Consideration For Forensic Engineers Of Various Technical Disciplines.

Sign in / Sign up

Export Citation Format

Share Document