4/23/2015· Failure Analysis
Weld Failure Analysis: Chair Failure Due to Inadequate Weld
By: Dr. Thomas Read
Read Consulting was asked to determine why a welded chair failed and caused injury to the person sitting in it.
articles
Liquid Impact Glass Failure Analysis
By: Dr. Thomas Read
Tel: (707) 544-2374
Email Dr. Read
Website: www.readconsulting.com
View Profile on Experts.com.
As "water hammer" (i.e. liquid impact) has the potential to cause glass bottle failure, Read Consulting LLC created two such failures to study the resulting fracture surface details.
Procedure: Two bottles were filled with warm water to within 3/4" of the top; they were then recapped. While holding the bottle upright, a rubber mallet was used to hit the top cap. After several blows, each bottle failed.
Results: Both failures initiated on the inside wall of the bottle where the base and the body intersect (heel). It is important to note that the bottle's inside wall is fire polished; thus, the glass strength should exceed 5,000 psi. This is confirmed by the very small fracture mirror at each origin. The small mirror indicates that the initiating stress was very high. In addition, the initial fracture is perpendicular to the axis of the bottle. This indicates that these failures are caused by downward forces created by the water. Thus, this is an impact failure; it is very different than a failure caused by high liquid pressure which results in cracks along the bottle axis.
Photographs: Below are photographs of the failed bottles:
Both bottles fractured at the heel (i.e. intersection of the sidewall and the base).
Fracture Origins
Bottle 'A' Fracture Origin
Bottle 'B' Fracture Origin
Dr. Thomas L. Read, CEO of Read Consulting received his PhD. from Stanford University in 1972. He has over 25 years of manufacturing experience in electronics, metallurgy, factory safety, failure analysis, glass fracture, glass failure and bottle failure. As a member of the electronics industry, Dr. Read has earned process patents and has an extensive background in manufacturing techniques. In parallel, he has spent over twenty five years as a consultant to attorneys and engineers in the areas of failure analysis, metallurgy, glass fracture, glass failure, bottle failure, factory safety, manufacturing problems, intellectual property and patent disputes.
©Copyright - All Rights Reserved
DO NOT REPRODUCE WITHOUT WRITTEN PERMISSION BY AUTHOR.
Related articles
7/3/2013· Failure Analysis
Forensic Clues: Fiberglass Failure
Safety Engineering Resources has had the opportunity to learn a great deal about using fiberglass in structural applications, which are simply applications that must support some sort of load. Using fiberglass as a structural material was brought about by the advances made by organic chemists in recent decades in the field of plastics.
2/26/2014· Failure Analysis
Forensic Clues: Elderly Mobility Aids
A significant number of elderly persons experience falls every year. In 2010, 2.3 million nonfatal fall injuries involving elderly people were treated in emergency rooms around the country. In the same year, 21,700 elderly people died as the result of unintentional falls. Falls for elderly people are extremely hazardous as they may not recover from fractures and other injuries.
Follow us
