What I miss in this list is that Mechanica is limited in a number of ways, for instance in contact behaviour and non-linear materials. If you plan on using such features, Mechanica isn't really an option.
And finally: as far as I know Nastran is a lot more expensive than Mechanica, this might also be an important consideration in your choice.
---- "Hodgson schreef:
> I can't help feeling that this has been covered before, but...
> - Accuracy of results in both packages depends on the user. Both can
> produce reliable numbers if the model is set up correctly.
> - Mechanica has an upper size / complexity limit, due to memory.
> Nastran will just keep on grinding, using bigger and bigger swap files,
> no matter what (even if it takes days).
> - Ease of meshing: Mechanica wins hands-down. The meshing is completely
> automatic - although see the above point about accuracy, and my
> - The learning curve is shallower to begin with in Mechanica, but gets
> steep as you get into complex models, or ones where you need to start
> using mesh controls and the like to achieve the accuracy. Nastran takes
> more learning initially, but then you're more or less set up for
> - Mechanica's biggest asset is seamless integration with Pro/E. Once
> you've attached loads and constraints to your model, you can alter
> parameters (and even geometry) as much as you like, and just re-run the
> Other than that, Mechanica is generally quicker to use, certainly for
> simple models, although for analyses with multiple load cases the
> ability to edit the load deck for Nastran is nice. On occasion I've
> imported IGES files into Pro/E to analyse using Mechanica, because it
> seemed like the easiest way.
> With either package, be aware that you really need an understanding of
> FEA principles to guarantee reliable, accurate results. The biggest
> risk with Mechanica is probably that it's too easy, and too automated -
> users can get complacent, and trust the results without checking
> carefully. Nastran is probably better for training up good users...
> This should probably be on the proecae list, btw - I've cross-posted to
> there, and future replies should ideally be trimmed to that list only.