Countersunk friction head diameter 2

[CarlesFEA]

Dear experts,

For a countersunk bolt DIN7991 M6, what average friction head diameter should be taken into account for its calculation? Nothing appears to be stated in VDI 2230:2003 for countersunk bolts
I have found in

http://www.hexagon.de/info112/index.htm

that DKM = (Da+Di)/SQRT(2) for 90deg cone angle countersunk screws should be used. Any other references?

Thank you in advance

 

[Screwman1]

Does the fastener have a recess drive in it? Those parts are not designed for structural applications and if there is a recess drive you should not be using it in a joint that is critical enough to require joint design calculations.
The friction under the head of a countersunk head is complex because of the yielding in the countersunk and the force vectoring the goes on. When we have had to figure this out, we used a Schatz unit to pull off the u'head friction.

 

[CoryPad]

Yes, try Chapter 6, Figure 38 on page 448 of Modeling & Simulation for Material Selection and Mechanical Design. The chapter is written by Christoph Friedrich and the book was edited by George E. Totten, Lin Xie, and Kiyoshi Funatani. The book is available for preview at Google Books.

 

[CarlesFEA]

Thank's Screwman and CoryPad for your interest.

I was able to find what I was looking for in the document written by Mr. Friedrich.