Material Question

Hi  All 

This should be a simple question but I am struggling a bit to understand the documentation. Has anyone successfully modelled air using  "*EOS ,type=Ideal gas" in an ABAQUS Explicit analysis with Eulerian Elements? I can't seem to get the material to work....  It just states that the material has zero bulk modulus?

Do I need to specify the initial pressure or something? 

 

Thanks for the help.

 

John