Using materials assigned by a CAD designer
When you import a part geometry from NX to HyperMesh as a JT file, any materials assigned from Granta MI by the CAD designer will be grayed-out. This indicates that the part geometry contains a reference to a material that is not currently in HyperMesh.
To bring the data required for simulation into HyperMesh, you need to re-assign the materials.
To update the materials with data for simulation:
At the top right of the assignments
panel, click 
Assign
default simulation data to all components.
Assign
default simulation data to all components.