Abaqus, UMAT, Constitutive law, Powder

Dear all,

I have several questions about how to use existing constitutive law of material to code UMAT in Abaqus. I have carried out experiment for several powder materials, including metal, ceramic, polymer powders. The powder aggregate is compacted in a cylindrical die. After the compaction, relationships between axial stress and axial strain, radial stress and axial strain are obtained. The material under such condition is always treated as elastic plastic material.

My questions are:How can I code such material into UMAT? Would it be an appropriate way to simulate other loading conditions using this type constitutive law (from closed die loading condition)? If not, what condition can this constitutive law be used for simulation. Does it mean that the constitutive law is just a stress strain curve which can be simply fitted by a trend line?

Sam

University of Leicester, UK