Thread: Partial diff

HI everybody

Please help me about this problem. It made me crazy. I can't understand how has the equation (8) obtained??? I attached it.

so I'm sorry about my poor English.

Tank u very much

These equations are a little confusing. Equations (1), (2) and (4) all define and are set equal to 0. Need more info before I can say how (8) is arrived at. What is actually?

Thank u about your respone.
But we can ignore equations (1),(2) and just use of another equations. Please just use of equations (3),(4),(5),(6),(7) and (8). and sigma is a constant. and f is a yield function in plasticity. In fact, f represents a surface in the space of (sigma1,sigma2). I have uploaded piece of this paper for u, maybe that help.
Link of paper: [COLOR="rgb(0, 0, 0)"]Document1.pdf - 4shared.com - document sharing - download[/COLOR]
Thank u again

It's not a matter of ignoring equations; I'm saying they make no sense. I've looked at the paper and your equation (8) is not there. Are you talking about their equation (10)? That equation does make sense.

sorry
yes. equation (10)

I'll need the rest of the paper to see how are defined.