Fatigue failure: question about instantaneous zone size 2

[kingnero]

I recently changed jobs, from pure mechanical design and mechanical failure diagnostic (in CNC machinery, presses, ...) towards welding and metallurgy. I've got the basics of the welding part covered (IWE - International Welding Engineer), but lack the knowledge towards metallurgy and failure analysis.

When a shaft breaks due to a fatigue failure (by both bending and torsion) that is initiated by a small stress concentration, the cross section can tell a lot about the failure.

I would like to know some more about the beach marks, chevron marks, and more importantly something specific about the % remaining surface (=instantaneous zone?) - if you can tell if the part was correctly sized / overstressed / ...

a quick search came up with this link:

http://www.plant-maintenance.com/articles/rcfa.shtml

But I could very much use a good book where this is all explained in great detail.
Any suggestions?
many thanks in advance...

 

[metengr]

For good technical information on fatigue, I would go here

https://efatigue.com/

Second, use the search tool above and locate posts related to fracture.

 

[TVP]

kingnero,

If you are looking for only 1 book on failure analysis, then I would recommend ASM HANDBOOK Volume 11. It is the most comprehensive reference on the subject. If you and/or your employer can afford it, I highly recommend ASM HANDBOOK Volume 12 as well. The other ASM books, Handbook of Case Histories in Failure Analysis, Volumes 1 & 2, are also excellent references with many individual case studies on a variety of components that are described succinctly.

There is also a lot of information that can be freely obtained on the internet. Here are some links to a few items that I have found to be particularly good:

Chapter 6 Fatigue Failure Resulting from Variable Loading

http://highered.mcgraw-hill.com/sites/dl/free/0073121932/365766/chapter06.pdf

AMPTIAC Material Failure Modes – Desk Reference

http://ammtiac.alionscience.com/pdf/deskref.pdf

Fatigue Crack Propagation

http://www.asminternational.org/emails/enews/amp_pdfs/amp16605p039.pdf

A re-examination of failure analysis & root cause determination

http://www.matcoinc.com/files/PublicationPDFs/ReExaminationofFailureAnalysisPart12.pdf

NLR technical publications

http://www.nlr.nl/eCache/DEF/9/805....t5qicpa&cof=FORID:11&ie=UTF-8&q=fracture#1133

Google search for fractography limited to .pdfs

http://www.google.com/search?hl=en&...=&as_occt=any&cr=&as_nlo=&as_nhi=&safe=images

 

[kingnero]

metengr and TVP, many thanks for the links.

I will first browse through all the pdf's, and will see if I can convince my employer for the ASM handbook.

This will certainly put me forward in my attempt of better understanding the subject.
Many thanks again.

 

[jagad5]

Book suggestions:

Mechanical Behavior of Materials by Dowling - one of the best surveys of the topic of failure. All six reviewers give it 5 stars at Amazon.com

Failure of Materials in Mechanical Design by Collins - excellent summary of all types of failures.

Fundamentals of Metal Fatigue Analysis by Bannantine, Comer & Handrock

Metal Failures by McEvily - I'm just reading it now, also an introduction to the topic.

efatigue.com is an excellent resource, too.

If you're still interested in fatigue after reviewing one or two of these, you'll be a good judge of which advanced books are suitable for your specific interests.

None of these books does an adequate job of covering the statistical problems associated with fatigue. Read chapter 9 of MIL-HDBK-5 or MMPDS for a decent introduction to this topic. If you can find an older version of MIL-5, there is some info that was removed from later editions.

Doug

 

[kingnero]

thx for your reply, I'll see if I can get my hands on a few of those...

I appreciate the suggestions!

 

[desertfox]

Hi kingnero

Have a look at this on line article:-

http://www.pump-zone.com/articles/408.pdf

desertfox