Talk:Flow plasticity theory

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flow rule justification unclear in case of perfect plasticity

Hello there,

I really can't understand the justification for the flow rule in case of perfect plasticity. Please make it clearer. As I understand it so far we are saying that d_sigma = 0 if plasticity starts. I agree with this. But now I don't understand where the co-directionality comes from. You cannot state from something like <u,v> = 0 and <u,w> = 0 that v and w are co-directional. For this u must be nonzero. But as I understand it, this argument is used here... I would be glad if someone updates this to explain it better.

Thanks,

Adrian

The statement d_sigma = 0 should be an outcome of that result rather than a cause. Will correct when I get the time. Thanks for pointing it out. Bbanerje (talk) 01:03, 17 July 2018 (UTC)[reply]