# Elasto-plastic Hydrodynamic Materials (LAW3)

This law is only used with solid brick and quadrilateral elements.

It models the elastic and plastic regions, similar to LAW2, with a nonlinear behavior of pressure and without strain rate effect. The law is designed to simulate materials in compression.

The pressure and energy values are obtained by solving equation of state $P\left(\mu ,E\right)$ related to the material (/EOS).

- $a$
- Yield stress
- $b$
- Hardening modulus
- $n$
- Hardening exponent
- ${\sigma}_{\mathrm{max}}$
- Maximum flow stress
- ${\epsilon}_{p}^{max}$
- Plastic strain at rupture

`P`

_{min}, can be given to limit the pressure in tension. The pressure cut off must be lower or equal to zero. Figure 1 shows a typical curve of the hydrodynamic pressure.