Click on the Materials dialog box to delete an assigned or unassigned material from the Materials in Model list, provided that the material is not assigned to a shell or beam. You cannot delete any of the materials in the Materials in Library list.
If you did not previously assign the material to an entity, Creo Simulate deletes the material from the model database. If you assigned the material to an entity, you are prompted for confirmation to delete the material. If you click OK, Creo Simulate deletes the material from your model and the model database.