rotating beam fatigue testing problems
rotating beam fatigue testing problems
(OP)
I'm currently testing Ti6Al4V on the rotating beam fatigue test setup. the problem is that quiet some samples do break just at the end of their fixation. Actually all specimens were produced according to the relevant standards. We have been testing some other materials like TiCP, 316L Stainless, and so on without having problems. So far we tried to put a foil in between to avoid stress concentration but that doesn't change anything.
Has anyone experience with this system?
Regards
Frank
Has anyone experience with this system?
Regards
Frank





RE: rotating beam fatigue testing problems
Solution? I don't know. In the application I was dealing with, we couldn't find one other than reducing the bending load (which in your case, would defeat the purpose). Maybe you could use a titanium collet?
rp
RE: rotating beam fatigue testing problems
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Rust never sleeps
Neither should your protection
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RE: rotating beam fatigue testing problems
Regards
Frank
RE: rotating beam fatigue testing problems
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: rotating beam fatigue testing problems
"When the Eagles Fall Silent
The Parrots Start Jabbering".
W. Churchill
RE: rotating beam fatigue testing problems
RE: rotating beam fatigue testing problems
(This is for flat flex beams of 1095 steel HRc54 against A2 HRc58-62.)
I too noticed early failure and non-stress level related results due to fretting damage.
Nick
I love materials science!
RE: rotating beam fatigue testing problems
@metalguy
I've tried several ways to avoid the friction by lubrication. actually non of them worked so far. We do have a special high moly grease and that doesn't change anything. I've also tried to work compleately "degreased" but that didn't help as well.
@NickE
I didn't think of that up to now. As we only had 0.11mm (.0043") I tried this. the advantage is that even as we had very vew vibrations the vibrations are even more reduced - BUT now i have the new problem that it is very hard to fix it to avoid a slip out of the test specimen - that happend now twice to me but I will try it again and I'll get some thicker teflon tape.
of course I'm still open for other inputs and I'll keep you infromed!
Regards
Frank
RE: rotating beam fatigue testing problems
In the past I have used very thin metal foil liners. The other thing is to run samples in under light load for a short period and then inspect to make sure that you have a good fit.
= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection
http://www.trent-tube.com/contact/Tech_Assist.cfm
RE: rotating beam fatigue testing problems
Regards
Frank