Shaft failed due to reversed torsional fatigue?
Shaft failed due to reversed torsional fatigue?
(OP)
Hi Everyone,
I got this failed shaft from work (please see the attached). It's the main drive shaft for our Bath Tissue Converting machine - we called it the knock off paddle. Based on what I saw and what I read from the book "How Components Fail", it looks like a Reversed torsional fatigue, but there is a plstic deformation in the centre, so I hesitated a bit to come to conclusion. Unless it goes again, I probably won't spend the time per my Manager to do a full scale stress analysis, bending moment diagrams and stuff (not to say we don't have the resources but the lack of that kind of information provided by OEM). What I wish to see is based on your experience, at a glance, do you think it is a reversed torsional fatigue?
Thanks a lot! :)
K
I got this failed shaft from work (please see the attached). It's the main drive shaft for our Bath Tissue Converting machine - we called it the knock off paddle. Based on what I saw and what I read from the book "How Components Fail", it looks like a Reversed torsional fatigue, but there is a plstic deformation in the centre, so I hesitated a bit to come to conclusion. Unless it goes again, I probably won't spend the time per my Manager to do a full scale stress analysis, bending moment diagrams and stuff (not to say we don't have the resources but the lack of that kind of information provided by OEM). What I wish to see is based on your experience, at a glance, do you think it is a reversed torsional fatigue?
Thanks a lot! :)
K





RE: Shaft failed due to reversed torsional fatigue?
RE: Shaft failed due to reversed torsional fatigue?
RE: Shaft failed due to reversed torsional fatigue?
Yes I agree with the other posters, have a look at this link just for further information
http://www.scarborough.gov.uk/pdf/09-10-027-Report...
RE: Shaft failed due to reversed torsional fatigue?
Check out any Mechanical Engineering Design books that deal with stresses and you will find a section on stress concentration factors. This and maintaining a Factor of Safety of >1.5 as served me well. (Personally I try to stay above a Factor of Safety of 2 if at all possible.)
RE: Shaft failed due to reversed torsional fatigue?
RE: Shaft failed due to reversed torsional fatigue?
How long was it in service?
RE: Shaft failed due to reversed torsional fatigue?
The shaft was in a pulley/sprocket
No record of replacement of this shaft since the machine was commissioned but our work order system is only good from year 2010.
Thanks!