Pressure Traction Law

This traction law creates a constant stress that is normal to the crack surface. It models a pressure loaded crack. The stress can be entered in one of two ways:

• stress - Enter constant normal stress (in MPa). Use negative stress for a pressure loaded crack.
• function - alternatively, the stress can be entered as a <a href="function.html">user-defined function</a> of time (giving stress in MPa). If a function is used, any entered stress property is ignored.

Experience shows that apply full stress from the start of calculation can cause large, local vibrations and lead to unstable results. If it often better to use the function option and ramp the stress to desired value.