Regarding NASTRAN nonlinear analysis capabilites, MSC has been working on the so called "Sol 400" which is becoming comparable in performance and capabilities to other commercial non-linear FEA codes.
I removed a lot verbage from this article that seemed a little too much like marketing for MSC and NASTRAN. I have both MSC.Nastran and NX.Nastran on my computer as well as Femap and MSC.Patran. I use them all day at work. However, I have also used other FEA solutions such as ABAQUS, ALGOR, ANSYS and I would not say that NASTRAN is the best or even the most generic. It is the oldest of those and is widely used. However, because of its age it is at times a combersome tool. The process of building, submitting, and anaylzing results is not far in principle from how it was done 40 years ago. I have also heard from others that the non-linear analysis capabilities of NASTRAN are far behind other software. I don't need to run non-linear models often so I haven't hit any limitations yet.
I was especially struck by the sentence that said that many/most contracts require NASTRAN be used for structural analysis. That is just not true. It may be, however, that a prime contractor will require a subcontractor to use the same software for building models so that they can be combined eventually with what the prime is working on. This may be a case when NASTRAN would be mandated. Still, I have never seen a contract (whether as prime or sub) that required NASTRAN. We work over 60 contracts at one time—both commercial and military.
A better way perhaps to think of the position of NASTRAN relative to other finite element solvers is an anology to Microsoft Word. It is the most widely used word processor and many people know how to use it. Also, many people respect its capabilities. However, not many people would claim that it is the most useful or advanced word processor or document creator. Professionals will often use something more advanced that better meets their needs— especially in publishing. Jebix 21:50, 7 July 2006 (UTC)
One thing VERY annoying that also keeps coming back: http://www.nenastran.com./newnoran/nastranAdditionalMaterial
Do Autodesk have some agreement to redistribute NASTRAN?
This is not MSC Nastran
There is a box that states that Nastran is developed by MSC Software, the latest release is version 2014, and the the license is Proprietary EULA. This is not accurate, MSC Software develops MSC Nastran.