09-07-2017, 08:54 PM
Ah, I see what you mean - I think I can visualize that, in that once the surface is penetrated it wouldn't take any more force to sever the remainder (in fact, the momentum from the initial breakthrough might reduce the pressure required). Thanks for clarifying. That notwithstanding, I feel like the initial separation still requires some displacement of material, even if it's only a matter of microns, and at the microscopic level the wedging effect of the edge would require more pressure as the angle becomes more obtuse. If, for example, the edge is half a micron, and it had to penetrate 10 microns to initiate the separation, there would be significantly more surface area in contact with the media, and a significantly more material being pushed further "sideways," at a 40 degree edge vs a 25 degree edge. I think that would increase both the friction and the surface area in contact with the media, both of which would increase the required pressure. But, I'm basing all of this on my visualizations - I'd love for someone to tell me I'm wrong, and why. I only really learn when I'm wrong.