force to penetrate of slip teeth into pipe wall

[DowneastTech]

I need to calculate the force required to indent slip teeth into pipe od to a given depth of a few thousandths of an inch (variable). It is a plastic-flow problem that so far eludes me. The teeth are much harder than the pipe and the pipe is ductile steel. Strain hardening need not be considered. Can anyone suggest a good way to calculate this force?



DowneastTech
Mechanical Engineer
Magnus R & D, Cypress, TX

 

[cab1990]

DET,

My experience is that you don't have much choice here. The problem is that there is no closed form solution for plastic deformation. I would suggest that you perform a finite element analysis with elastic perfectly plastic material properties. If the strains do not exceed 5% then the elstic perfectly plastic analysis will be accurate. If the strains are much higher, then the accuracy will suffer. Beyond 10% strain, you will need to develope a true-stress true strain material model to get an accurate force. Good luck.

cab1990