Fracture Mechanics - Stress Intensity Factors 2

[ziptron]

Hello All,

I was wondering if anyone had a good source for where I could find stress intensity factors for a tube (similar to a pipe) loaded in bending.

I have a tube which failed for me and I noticed that it was initiated by fatigue failure. Fatigue failure produced a flaw within the tube and it eventually failed from overload. I'm curious what the final force was that caused it to finally rupture.

I'm thinking I could use Fracture Mechanics for this.. K = Y(Sigma)root(PIa) or something similar.. but I need to know that Y term..

Any ideas, and any comments regarding my methodology would be much appreciated. Thanks!

 

[rb1957]

stress intensity factors ... Rooke and Cartwright is a good place to start (it's like petersen is for stress concentrations).
to determine the load causing failure, you'll also need the material toughness (Kc, possibly KIc if the tube is very thick). i suspect too that you've got a complex loading (pressure in the tube, bending, ...) and possibly temperature effects ... this isn't going to be a simple exercise ... good luck !

 

[SJones]

In order to achieve your goal you are going to have to work backwards through an engineering critical assessment process such as that outlined in British Standard 7910. If your interest is purely personal, you may find yourself giving up some way in!!

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[corus]

Look at this paper

http://www.eurofitnet.org/sintap_BRITISH_ENERGY_sif-ll_final.pdf

 

[metengr]

The Y term would be assumed based on a semi-elliptical surface flaw.

http://www.tech.plym.ac.uk/sme/inte...hanics/StressIntensity/Questions/problem9.htm

 

[ziptron]

Thank you all for your generous information!

I will definitely look through all of the resources you've provided!

Thanks!