More about MD Nastran
You can have the 11.1 version of MD Nastran 400 MB from this website. MSC.Software Corporation provides this program for free. Among the software versions, the most installed ones are 10.1 and 6.0, which run under Windows 7. Mdnastranw.exe and nastranw.exe are the most popular installer names of this tool you may come across. The download link of the program is safe to use.