scholarly journals Forensic Engineering Investigation Of An Alleged Plastic Chair Failure

2010 ◽  
Vol 27 (2) ◽  
Author(s):  
John P. Leffler
Keyword(s):  
Standard Test ◽  
Test Method ◽  
Destructive Testing ◽  
Expert Opinions ◽  
Show Evidence ◽  
Forensic Engineering ◽  
The Subject ◽  
Residential Use ◽  
Engineering Investigation ◽  
The Chairs

Several Identical One-Piece Molded Plastic Chairs Were Purchased By A Mental Hospital For Use In An Outdoor Smoking Area. The Chairs Were Labeled As Being For Residential Use. A Hospital Patient Alleged That While Seated In One Of These Chairs, The Chair Failed And He Fell Backward, Striking His Head And Suffering Injury. The Subject Chair Did Not Show Evidence Of A Failure That Would Correlate To The Plaintiff Allegation. Analysis And Destructive Testing Was Conducted On Several Of The Remaining Chairs, Referencing The Astm Standard Test Method For Residential And Nonresidential Molded Plastic Chairs. Adverse Expert Opinions Were Also Addressed.

scholarly journals Validation of Microscopy Measured Porosity in Carbon Fibbers Composites

2019 ◽  
Vol 26 (4) ◽  
pp. 83-90
Author(s):  
Arnold Jędral ◽  
Anna Bona
Keyword(s):  
Carbon Fibre ◽  
Standard Test ◽  
Test Method ◽  
Testing Methods ◽  
Destructive Testing ◽  
Reinforced Plastics ◽  
Reinforced Plastic ◽  
Carbon Fibre Reinforced Plastic ◽  
Observation Method ◽  
Quality Instrument

AbstractOne of the most common defects in carbon fibre reinforced plastics (CFRP) is porosity. Too much of those defects could be serious problems to mechanical properties, which directly take effect on elements safety, like aircrafts. Therefore, the evaluation of porosity is very important test. Microscopic observations are widely used as a quality instrument in materials and constructions inspections. Cross section image of a material is easy to prepare and analyse. Porosity of a carbon fibre reinforced plastic can be clearly spot in such kind of images. Study shows that in the most cases porosity appear between layers of fibres, rather between fibres. Unfortunately, image from microscope is only 2D picture from a small representative region. Because of that, comparison of 2D image to a real porosity distribution in all volume of a material is very difficult. To verify 2D microscopic observation method is necessary to perform another kind of tests. In this article, authors focused on non-destructive (NDT) and destructive testing methods. 2D porosity images from light microscope were compared with three different testing methods: ultrasonic test (UT), computed tomography (CT) test and constituent content of composite materials standard test method according to ASTM D3171 – 15, procedure B. Porosity results obtained from dissolution of resin from the carbon-epoxy resin sample.

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 Investigation Of a Fall From A Construction Machine

2009 ◽  
Vol 26 (2) ◽  
Author(s):  
John P. Leffler ◽  
Schlender Erich
Keyword(s):  
Machine Design ◽  
Construction Machine ◽  
Forensic Case ◽  
Forensic Engineering ◽  
The Subject ◽  
Engineering Investigation

Each Construction Machine Design Presents Unique Challenges For Mounting And Dismounting Byorkers. A Forensic Case Involved A Worker Fall From Around The Turret Platform Of A New Digger Derrickruck, Parked On Level Concrete. The Case Involved Analysis Of Osha, Ansi, Fmvss, Sae, And Isotandards, And Their Scopes, Relevance And Interpretations. The Analysis Also Focused On Operator Instructions,He Design And Fabrication Of The Access Systems, The Worker Proportions, Feasible Competitoresigns, And Feasible Fabrication Options For The Subject Digger Derrick.

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