Failure Analysis: Product Liability & Personal Injury Involving a Broken Grinding Wheel
This grinding wheel was part of a product liability and personnel injury case. It was claimed that the subject wheel had unexpectedly failed (i.e. flown apart) and an escaping piece had hit the plaintiff in the face causing serious injuries. According to the user, the grinder with the wheel was purchased approximately one hour before the grinding wheel failure.
Failure Analysis: Collapse of Plastic Chair
A failed plastic lawn chair was examined to determine the cause of failure. This chair failed on the premises of a restaurant In this study the subject chair is examined and compared to several exemplar purchased at the same time. The objective of this study is to determine the cause of failure.
Root Cause Failure Analysis of Tempered Glass Door
Glass Failure Analysis Expert Witness performs a failure analysis of a several tempered glass doors that had "spontaneously" failed at a construction site. The objective of this glass failure analysis is to determine the cause of failure and make recommendations to the contractor.
Metal Failure Analysis: Metal Food Contaminant Failure Analysis
Materials failure analysis expert performs a failure analysis to determine the source of a metal piece found in tomato product.
Plumbing Failure Analysis: Stress Corrosion Cracking of Yellow Brass
A plumbing failure analysis was performed to determine why a cold water supply line to a bathroom sink had failed after only one year of service.
Failure Analysis of a "Exploding" Beer Bottle: Product Defect, Product Liability
A glass failure expert witness performs a root cause failure analysis on an exploding beer bottle. The object of this root cause failure analysis is to determine the cause of the bottle failure.
White Paper: Reverse Engineering
Before expending the effort necessary to reverse engineer a device or object, it must be definite that the object under study is not covered by one or more patents. This avoids a dispute over patent violations. Once it has been established that no patent coverage exists, one can use multiple techniques to reverse engineer a product. These are summarized below:
Failure Analysis of a Failed Ceramic Water Holding Tank on a Toilet
The cracked tank was first inspected in the "as received" condition. In this condition it was cracked, but it was still whole. Next, the failed tank was separated by pulling it apart. This was done to expose the fracture surfaces of the main crack. This allowed for a complete failure analysis and for a determination of where the crack initiated.
Failure Analysis of a Broken Jam Jar
Glass fractography is the most effective method for determining why a glass object, such as a bottle, failed. This technique consists of examining the fracture surfaces of the failure for artifacts such as Wallner lines and using them to trace the crack back to its origin. Once the origin has been identified, it can be examined in detail with a microscope to determine the cause of the failure.
Wine Bottle Failure Analysis
Note: Glass Fractography is the most effective method for determining why a glass object, such as a bottle, failed. This technique consists of examining the fracture surfaces of the failure for artifacts such as Wallner lines and using them to trace the crack back to its origin
Cliff Knight is President of KnightHawk Engineering and a Professional Engineer with 36 years of experience. Besides his corporate responsibilities as President, Mr. Knight is also Chief Engineer. Mr. Knight specializes in design, failure analysis and troublshooting in static rotating equipment. He has 21 years of experience in utilizing computer applications, which include Finite Element Method, Numerical Modeling, Heat Transfer, Pipe Stress Analysis and Computer Fluid Dynamics.
