# Meaning of yield function in elastoplasticity

1. Jun 10, 2005

### joelle

i'd like to know if it's possible what the meaning of yield function in elastoplasticity.
Also what is the concept of inelastic potential
i'll be thankful if someone can help me

2. Jun 10, 2005

### Staff: Mentor

Try these references for now -

http://www.ce.washington.edu/~geotech/const_model/ge_plastic/node2.html

With regard to inelastic potential, try

http://gltrs.grc.nasa.gov/reports/2003/TM-2003-212382.pdf - document page 3 (page 7 of pdf file).

Ref 10. Khan, A.S.; and Huang, S.: Continuum Theory of Plasticity. John Wiley and Sons, Inc.,
New York, 1995.

3. Jun 10, 2005

### PerennialII

Nice sources, in short the ingredients of typical plasticity models :

yield function : say $f(\sigma, q_{\alpha})$ where $\sigma$ is the true stress tensor and $q_{\alpha}$ are a set of internal variables - control onset and progress of plasticity

flow rule, flow potential - govern plastic flow, the increments of plastic strain, for example in incremental plasticity $\dot{\epsilon_{p}}=\dot{\lambda}\frac{\partial\psi}{\partial\sigma}$, where $\psi$ is the flow potential.

evolution equations - govern the behavior of internal variables, like strain hardening etc.

... typically metal plasticity models are associative, i.e. the flow potential and yield function are identical.