I'm trying to create some custom matl's that we might be able to use with simulation xpress. Yes we just have the xpress now, but perhaps we could move into the fuller package. Anyway I found some good sites, to help with the necessary properties, such as matweb.com, but it leaves a few categories with real crazy conversions in order to maintain the sw units, like btu-in/hr-ft²-°F to Btu/(in.sec.°F), & µin/in-°F to /°F. I'm not up on those conversions.
Anyway I'm wondering, concerning those that have the need to enter various custom materials for simulation purposes, what they've found to be the best sources, maybe even free, to match up with the SolidWorks.
Open up a new part file, go to TOOLS>OPTIONS>DOCUMENT PROPERTIES>UNITS and change the units to match the units of the data you are provided.
This will allow you to enter the information as is and let SW do the conversion for you. When you use the material in another part with different units assigned the values will automatically show up in the assigned units.