# Meaning of yield function in elastoplasticity

#### 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

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#### Astronuc

Staff Emeritus
Try these references for now -

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

With regard to inelastic potential, try

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

an inelastic potential function based on the Drucker-Prager yield
criterion (Ref. 10) . . .
Ref 10. Khan, A.S.; and Huang, S.: Continuum Theory of Plasticity. John Wiley and Sons, Inc.,
New York, 1995.

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#### PerennialII

Gold Member
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.

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