ring compression test for friction coefficient

[stel8]

I am interested in more info, especially the formulas to draw the curves for friction coefficient.
Thank you very much for your reply.
sgc

 

[aviat]

Here is a naca report but it does't include any formulas. If you have access to the old SAE Transcripts and Jounals there is probable information in one of them.

http://naca.larc.nasa.gov/reports/1947/naca-tn-1249/index.cgi?page0015.gif

 

[stel8]

I was not clear enough. I am interested in compression test for metal forming operation. The test was developed by Avitzur and continued by Male and Cockcroft.
Thx for info and sorry for confusion.