Your browser is currently set to block JavaScript.

For full functionality of this site it is necessary to enable JavaScript. Here are the instructions how to enable JavaScript in your web browser.

After enabling javascript, please refresh the page to go back to experts.com site with full functionality

Would you turn off/on JavaScript?

It's a widely used language that makes the web what it is today, allowing for websites to be more responsive, dynamic, and interactive. Disabling JavaScript takes websites back to a time when they were simple documents without any other features.

What are the advantages of using JavaScript?

Speed. Since JavaScript is an 'interpreted' language, it reduces the time required by other programming languages like Java for compilation. JavaScript is also a client-side script, speeding up the execution of the program as it saves the time required to connect to the server.

banner ad
Experts Logo

articles

Elements of Failure Analysis

By: Wayne Reitz, PhD, PE
Tel: 701-235-0859 - Fax: 701-235-6122
Email: Email Dr. Reitz
Website: www.reitzmetallurgy.com

Profile on Experts.com.

Abstract

Failure analysis is conducted to determine the root cause of failure. Sometimes these failures are catastrophic, e.g., Titanic. Other times the failures are a nuisance, e.g., failed o-ring in plastic faucet water valve. In both cases, the component failed unexpectedly, which can result in injury or death, not to mention financial loss due to unscheduled downtime. By using the information presented in the failed component a company could reduce, or eliminate, the possibility of re-occurrence of that type failure. This paper will discuss failure analysis in general terms and provide several case studies. The areas of failure analysis to be presented include typical tools, steps in conducting a failure analysis, theory of crack propagation, typical failure mechanisms, and case studies.

Introduction

It may sound like a bad joke, but what do manufacturers, insurance companies, and lawyers have in common? From an engineering viewpoint the common factor is providing engineering analysis to determine the root cause of why a component failed. Manufacturing companies want to save money, be more efficient, reduce down-time, and have proper preventive maintenance programs. Insurance companies do not want to pay a claim if abuse of the equipment was responsible for the failure and resulting claim. Lawyers need engineering data to assist in proving their case.

Failure analysis is a broad discipline that includes metallurgy and mechanical engineering. Some personal attributes of a good failure analyst include common sense, the willingness to expect the unexpected, and of course, a strong understanding of the engineering theory. Some of the typical tools include various forms of examination, e.g., visual and electronic. There are numerous steps in completing a failure analysis study and they should be performed in the proper sequence.

This paper introduces the above concepts and provides a few case studies showing how engineering knowledge and the ability to apply it work in these problem solving scenarios.

Typical Tools
Failure analysis provides insight into failure mechanisms if the analysis is thorough and accurate and all the necessary tests are performed. If the analysis is incomplete, then the wrong conclusions will be reached with possible serious future consequences. This paper only addresses a few of the tools, but they are all inter-related. There are several references the reader can obtain to become familiar with all the possible tools available.(1, 2, 3, 4)

Visual exam
The overall condition of the component is quite important, beyond just looking at the fracture surface. It is important to determine the exposure of the entire component to the environment, which includes temperature, acid, tensile or compressive stresses, impact forces, corrosion, and wear. Just receiving a portion of the failed component, i.e., the fractured surfaces will not allow a fully justifiable conclusion to be determined. The author experienced this very concept a few years ago, which made the investigation quite challenging.(5)

Macroscopic exam
The initial view of the fractured surface provides many clues that will aid the failure analyst in determining the responsible failure mechanism. The presence of oxide on a portion of the fracture surface indicates a long exposure to the atmosphere, a smooth surface could indicate rubbing of the mating surfaces after fracture. Certain features will assist the failure analyst in where to concentrate the area of evaluation, e.g., ratchet marks and beach marks. There are several excellent references that can aid the reader. (1, 6, 7)

. . . Continue to article and footnotes (PDF).


Wayne Reitz, Phd, PE, performs metallurgical evaluations, mechanical testing, failure analysis, and forensic metallurgy for industry, insurance claims, and as expert testimony.

See Dr. Reitz's Profile on Experts.com.

©Copyright 2000-2007 - All Rights Reserved

DO NOT REPRODUCE WITHOUT WRITTEN PERMISSION BY AUTHOR.

Related articles

thomas_read_photo.jpg

2/3/2014· Failure Analysis

Failure Analysis: Manufacturing Engineer Examines the Root Cause of Automobile Rear View Mirror Failures

By: Dr. Thomas Read

The root cause of the failure of customer returns of heated automobile rear view mirrors was investigated.

thomas_read_photo.jpg

5/21/2012· Failure Analysis

Failure Analysis: Product Liability & Personal Injury Involving a Broken Grinding Wheel

By: Dr. Thomas Read

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.

thomas_read_photo.jpg

4/12/2021· Failure Analysis

Glass Failure Analysis: Glass Oven Dish Failure

By: Dr. Thomas Read

The annealed borosilicate glass pie plate failed as a result of “thermal shock”. There were multiple origins for the failure, and these all initiated at damage sites on the bottom of the Pyrex baking dish. It appears that the bottom of the pie plate was convex. Thus, setting the dish down and moving it on hard (abrasive) surfaces such as tile or granite counters created bottom “rim” damage.

;
Experts.com-No broker Movie Ad

Follow us

linkedin logo youtube logo rss feed logo