NX Nastran is a general purpose structural analysis software application that Siemens PLM Software independently developed based on the same source codes of MSC Nastran that MSC Software had developed with more than 1,000 man-year investment in research and development. Nastran has been used widely in all the major manufacturing fields.

http://www.plm.automation.siemens.com/en_us/products/nx/for-simulation/