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 of An LP-Gas Installation And an Analysis Of Odor Fade

2012 ◽  
Vol 29 (2) ◽  
Author(s):  
Robert N. Anderson ◽  
Petersen James A.
Keyword(s):  
Standardized Testing ◽  
The United States ◽  
Impact Performance ◽  
Performance Improvements ◽  
Supply Tank ◽  
Gas System ◽  
Hybrid Iii ◽  
Forensic Engineering ◽  
Testing Standards ◽  
Engineering Investigation

The First Part Of This Presentation Is A Case Study Involving A Domestic Propane Gas System, Having A Buried Line Between The Supply Tank And The Residence. The Gas Line Was Pierced During A Landscaping Project. This Breach Was Undetected And Gas Leaked Underground; Migrating Towards The House Where It Entered Under The House. The Fugitive Gas Found A Source Of Ignition, Resulting In An Explosion And Death Of The Single Occupant. Odorant In The Gas Apparently Did Not Warn The Occupant. What Performance Improvements Correlate? Dot And Non-Dot Helmets Were Tested To Determine Impact Performance At Velocities Exceeding Standardized Testing Velocities. Three Types Of Dot Approved And Three Types Of Non-Dot Approved Helmets Were Tested At Two Speeds Outside Of The Federal Testing Standards In The United States. The Analysis Was Performed Using An Inverted Pendulum Sub-System Experimental Device With A Hybrid-Iii Anthropometric Dummy Cranium And Neck. Results Quantify The Performance By Category, Model, And Experiment By Test Metric.

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.

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 Lessons Learned from a Forensic Engineering Investigation of a Scaffold Support Failure

2021 ◽  
Vol 38 (1) ◽  
Author(s):  
John Schwartzberg
Keyword(s):  
Stress Analysis ◽  
Lessons Learned ◽  
Expert Opinions ◽  
Structural Capacity ◽  
Physical Testing ◽  
Fundamental Cause ◽  
Cause Of Failure ◽  
Forensic Engineering ◽  
Engineering Investigation ◽  
Metallurgical Evaluation

During use, a scaffold support allegedly failed, causing injuries to the user when he fell. The plaintiff’s expert identified a defective weld as the cause of failure and opined that the product was improperly designed. This paper examines methods used to evaluate the circumstances of and claims made regarding the incident. A combination of engineering methodologies, including metallurgical evaluation, stress analysis, and physical testing, was used to examine the plaintiff’s claims of deficiencies in the design and fabrication of the product. The engineering methodologies refute claims made about the structural capacity of the product by the plaintiff’s expert and the fundamental cause of failure. This paper examines themes related to the presence of apparent defects/failure and the necessity of verifying postulated hypotheses. It also examines the efficacy of analysis and testing as part of implementation of the “forensic engineering method” in verifying or rejecting hypotheses en route to offering expert opinions in forensic engineering investigations.

scholarly journals Forensic Engineering Use Of The Safety Hierarchy

2005 ◽  
Vol 22 (1) ◽  
Author(s):  
John N. Schwartzberg
Keyword(s):  
Forensic Analysis ◽  
Case Histories ◽  
Analytical Technique ◽  
Root Cause ◽  
Hazard Control ◽  
Hazard Avoidance ◽  
Cause Of Failure ◽  
Forensic Engineering ◽  
Process Failures

The Safety Hierarchy Is A Recognized Linear Logical Approach To Hazard Control Most Commonly Utilized By Safety Professionals In Hazard Avoidance. In This Paper, Use Of This Method Of Analysis Is Introduced As A Method Of Forensic Analysis Of Product Failures, Workplace And Premises Liability Accidents, And Process Failures To Help Identify The Root Cause Of Failure And The Role Of The Responsible Entity In Causation. Examples And Case Histories Will Be Used To Demonstrate The Effectiveness Of The Analytical Technique.

scholarly journals Forensic Engineering Analysis of Common Failures and Inspection Procedures for Residential and Commercial Chairs

2020 ◽  
Vol 36 (1) ◽  
Author(s):  
Anthony Sasso
Keyword(s):  
Paper Industry ◽  
Engineering Analysis ◽  
Safety Standards ◽  
Root Cause ◽  
Maintenance Program ◽  
Cause Of Failure ◽  
Forensic Engineering ◽  
Inspection And Maintenance ◽  
Materials Used ◽  
Mechanism Of Failure

Chairs have been designed, manufactured, and used by humans for thousands of years. Eventually, all chairs wear out and fail. When someone is injured due to this failure, costly litigation can ensue. Forensic engineers are consulted to investigate the root cause of failure, and whether the mechanism of failure could have been detected prior to the accident to avoid injury. Materials used in chair manufacturing and several examples of failures are discussed in this paper. Industry safety standards and manufacturers’ guidelines are used as a basis for a proposed inspection and maintenance program for chair owners.

Identifying the Root Cause of Source-Drain Leakage Caused Soft Fail in Advanced Bulk FinFET Devices

2018 ◽  
Author(s):  
Liangshan Chen ◽  
Yuting Wei ◽  
Tanya Schaeffer ◽  
Chongkhiam Oh
Keyword(s):  
Careful Analysis ◽  
Physical Analysis ◽  
Device Structure ◽  
Tem Analysis ◽  
Root Cause ◽  
3D Architecture ◽  
Cause Of Failure ◽  
Electrical Analysis ◽  
Electrical Data

Abstract The paper reports the investigation on the root cause of source-drain leakage in bulk FinFET devices. While the failing device was readily isolated by nanoprobing technique and the electrical analysis pinpointed the potential defect location inside the Fin channel, the identification of physical root cause went through extreme challenges imposed by the tiny-sized device and the unique FinFET 3D architecture. The initial TEM analysis was misled by the projection of a species in the lamella surface and thus could not explain the electrical data. Careful analysis on the device structure was able to identify the origin of the species and led to the discovery of the actual root cause. This paper will provide the analysis details leading to the findings, and highlight the role of electrical understanding in not only providing guidance for physical analysis but also revealing the true root cause of failure in FinFET devices.

Failure Localization in a Multistage S-Band Power Amplifier

2016 ◽  
Author(s):  
Clarence Rebello ◽  
Ted Kolasa ◽  
Parag Modi
Keyword(s):  
Output Power ◽  
Power Amplifier ◽  
Fault Tree ◽  
Root Cause ◽  
Failure Investigation ◽  
Band Power ◽  
Cause Of Failure ◽  
Design Materials ◽  
Board Level ◽  
Failure Localization

Abstract During the search for the root cause of a board level failure, all aspects of the product must be revisited and investigated. These aspects encompass design, materials, and workmanship. In this discussion, the failure investigation involved an S-Band Power Amplifier assembly exhibiting abnormally low RF output power where initial troubleshooting did not provide a clear cause of failure. A detailed fault tree drove investigations that narrowed the focus to a few possible root causes. However, as the investigation progressed, multiple contributors were eventually discovered, some that were not initially considered.

Case Study—Failure Analysis of a Multiplexer

2016 ◽  
Author(s):  
Michael Woo ◽  
Marcos Campos ◽  
Luigi Aranda
Keyword(s):  
Failure Analysis ◽  
High Reliability ◽  
Component Failure ◽  
Root Cause ◽  
Knowing That ◽  
Cause Of Failure ◽  
The Cost

Abstract A component failure has the potential to significantly impact the cost, manufacturing schedule, and/or the perceived reliability of a system, especially if the root cause of the failure is not known. A failure analysis is often key to mitigating the effects of a componentlevel failure to a customer or a system; minimizing schedule slips, minimizing related accrued costs to the customer, and allowing for the completion of the system with confidence that the reliability of the product had not been compromised. This case study will show how a detailed and systemic failure analysis was able to determine the exact cause of failure of a multiplexer in a high-reliability system, which allowed the manufacturer to confidently proceed with production knowing that the failure was not a systemic issue, but rather that it was a random “one time” event.

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