Material rupture examples and explanations

4.1  Tensile test on steel.

For standard steel, the Johnson-Cook material law is, most of the time, the selected one. This is an elasto-plastic law which includes strain rate and temperature effects:

with:

 

p  = plastic strain

= strain rate

T = Temperature (in Kelvin degrees)

The plasticity hardening exponent

n must be less than 1.

 

The material behavior is coupled with the Johnson-Cook rupture criterion

Results: rupture under tension but not under compression as expected.

 

Selecting the tabulated material law coupled with the Johnson-Cook rupture model gives the same behavior and also rupture.