There is a vast range of materials that can be used to produce a plastic part, each contributing different qualities to the final product. To achieve the most accurate analysis results, it is important that the material you select for the simulation is similar to the actual material you have chosen for the part.
Autodesk Simulation Moldflow provides a wide variety of materials databases, which include thermoplastic materials, fillers, coolants, thermoset materials, and others depending upon your analysis.