## *DEFORMATION PLASTICITY

Keyword type: model definition, material

This option defines the elasto-plastic behavior of a material by means of the generalized Ramberg-Osgood law. The one-dimensional model takes the form:

 E\epsilon=\sigma + \alpha \left( \frac {\left| \sigma \right| }{\sigma_0} \right)^{n-1}\sigma (787)

where \epsilon is the logarithmic strain and \sigma the Cauchy stress. In the present implementation, the Eulerian strain is used, which is very similar to the logarithmic strain (about 1.3 % difference dat 20 % engineering strain). All coefficients may be temperature dependent.

First line:

• *DEFORMATION PLASTICITY

Following line:

• Young's modulus (E).
• Poisson's ratio (\nu).
• Yield stress (\sigma_0)
• Exponent (n).
• Yield offset (\alpha).
• Temperature.
Repeat this line if needed to define complete temperature dependence.

Example:

*DEFORMATION PLASTICITY
210000.,.3,800.,12.,0.4


defines a Ramberg-Osgood law. No temperature dependence is introduced.

Example files: beampl.