High Quality Content by WIKIPEDIA articles! NEi Nastran is an engineering analysis and simulation software product of NEi Software (formerly known as Noran Engineering, Inc.) Based on NASA`s Structural Analysis program, the software is a finite element analysis (FEA) solver used to generate solutions for linear and nonlinear stress, dynamics, and heat transfer characteristics of structures and mechanical components. NEi Nastran software is used with all major industry pre and post processors including Femap, a product of Siemens PLM Software, in house brands NEi Fusion, and NEi Works for SolidWorks.