scholarly journals Forensic Engineering Evaluation of Excessive Differential Settlement on Compressible Clays

2021 ◽  
Vol 37 (1) ◽  
Author(s):  
Rune Storesund ◽  
Alan Kropp
Keyword(s):  
Variable Thickness ◽  
Differential Settlement ◽  
Housing Project ◽  
Root Cause ◽  
Forensic Engineering ◽  
Thickness Layer

This forensic engineering (FE) study evaluated root cause errors associated with excessive differential settlements on a housing project constructed on top of a variable thickness layer of highly compressible clays. The structures were reported to have experienced differential settlements on the order of 2 to 10 in. across 40 ft. The FE study examined fundamental assumptions, granularity/resolution of the settlement and differential settlement analyses, and finalized grading plan vs. the conceptual grading plan used as a basis for the differential settlement predictions. The FE study found numerous discrepancies between the “idealized site” used as a basis of analysis and the “actual site” as constructed.

Effect of Scanning Direction on Microstructure and Mechanical Properties of Part Formed via Variable Thickness Layer Cladding Deposition

2019 ◽  
Vol 46 (8) ◽  
pp. 0802003
Author(s):  
周显新 Xianxin Zhou ◽  
辛博 Bo Xin ◽  
巩亚东 Yadong Gong ◽  
张伟健 Weijian Zhang ◽  
张海权 Haiquan Zhang
Keyword(s):  
Mechanical Properties ◽  
Variable Thickness ◽  
Scanning Direction ◽  
Microstructure And Mechanical Properties ◽  
Thickness Layer

Improved Fourier terrain correction, Part II

Geophysics ◽  
1996 ◽  
Vol 61 (2) ◽  
pp. 365-372 ◽  
Author(s):  
Robert L. Parker
Keyword(s):  
Power Series ◽  
Variable Thickness ◽  
Grid Point ◽  
Main Idea ◽  
Terrain Correction ◽  
Potential Fields ◽  
Fourier Methods ◽  
Convergence Problems ◽  
Thickness Layer ◽  
Level Plane

Fourier methods for potential fields have always been developed with the simplification that the calculation surface is a level plane. The Fourier approach can be extended to deal with an uneven observation surface. I consider the case of terrain correction for gravity surveys, in which the attraction of a variable‐thickness layer is calculated at points on its upper surface. The main idea is to use a power series in topographic height that is then converted into a series of convolutions. To avoid convergence problems, a cylindrical zone around the observer must be removed from the Fourier treatment and its contribution computed directly. The resultant algorithm is very fast: in an example based on a recent survey, the new method is shown to be more than 300 times faster than a calculation based on summing contributions from a column of material under each topographic grid point.

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.

scholarly journals Forensic Engineering Analysis Of A Propane fueled Residential Gas Explosion

2011 ◽  
Vol 28 (1) ◽  
Author(s):  
David S. Komm
Keyword(s):  
Gas Migration ◽  
Root Cause ◽  
Residential Heating ◽  
Gas Leak ◽  
Gas System ◽  
Flammable Gas ◽  
Forensic Engineering ◽  
Safety Features ◽  
Gas Leaks ◽  
Selection Of

The Use Of Liquid Petroleum Or Commercial Propane Gas (Hereafter Referred To As Propane) For Residential heating And Cooking Is Common In The Rural United States Where Providing The Infrastructure For natural Gas Distribution Would Be Too Costly. A Typical Installation May Include A 500 Gallon Pressurized vessel Containing A Mixture Of Liquid And Vapor Propane With The Vapor Fed To An Individual Residence through An Underground Line. Safety Features, Such As Odorization Of The Propane, Multi-Regulator Installations, prudent Selection Of Gas Line Components, And System Leak Checks Are Utilized To Prevent And/Or recognize Fugitive Gas Leaks.  in 2005 An Event Occurred In Michigan Which Involved A Flammable Gas Leak, Corrosion, Gas Migration through Soil, A Buildup Of The Flammable Gas, And Subsequent Ignition Resulting In An Explosion which Destroyed A Two Story Home. This Forensic Investigation Eventually Revealed That The Root Cause Of the Incident Lay In Actions Taken During The Original Construction. Some 16 Years After The Installation Of the Subject Gas System Circumstances Came Together To Create An Explosion.

scholarly journals Forensic Engineering Analysis of Toilet Connector Failures in a Class-Action Lawsuit

2015 ◽  
Vol 32 (2) ◽  
Author(s):  
James William Jones
Keyword(s):  
Class Action ◽  
Finite Element Analyses ◽  
Engineering Analysis ◽  
Root Cause ◽  
Industry Standards ◽  
Creep Analysis ◽  
Strength Tests ◽  
Single Overload ◽  
Forensic Engineering ◽  
Injection Molded

A major manufacturer of water supply lines that connect flushable toilets to house water piping was the object of a class-action lawsuit. The author examined a large number of failed and exemplar connectors, complete fill lines, and similar injection-molded products as well as visited failure sites with the goal of ascertaining the root cause of the failures. Forensic work included strength tests and finite element analyses to determine the expected life of the nuts, including single overload failure strength and creep analysis to predict life. Tightening tests using random subjects were conducted. A statistical analysis of the failures was also performed. The products of competing manufacturers were evaluated for comparison of similar designs. After much investigation and analysis, it was concluded that the design of the connector was not defective and met relevant industry standards.

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 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.

Sign in / Sign up

Export Citation Format

Share Document