NEi Nastran Composite Analysis

[NKUltra]

Hi everybody,

this is my first post on this forum so I would really appreciate your help on this one. I apologize if somebody already asked the question but I could not find answer anywhere.

To put things simply, I am using NEi Nastran (v 2.1) for the first time as a composite modeler so I am getting a bit frustrated with how it works. I am trying to design a wind turbine blade that consists basically from only 3 parts (2 shells and the shear web part inside), but within these, exists tenths of regions with different ply/thickness properties. From my current understanding, one part can contain only one physical properties card which basically means that I have to make a new part for every section of the shell that contains different thickness and unify them in final assembly.

This approach is a bit of a problem, not only because I would have to model almost 100 regions /parts as separate entities, but because I could not find a way to heal gaps between surfaces and meshes between assembly components (only within part). I made original geometrical model in ProE Wildfire.

So basically my question is how do you model composite part with multiple thicknesses in NEi NASTRAN?

Any help would be highly appreciated

NK

 

[stressebookllc]

I think what you are alluding to are ply drop offs or pick ups. The only way I can think of is to have different lay ups. Let us see what others say.

http://www.stressebook.com

Stressing Stresslessly!

 

[NKUltra]

Thanks for the answer. Unfortunately I am not alluding to the ply drop offs.

I apologize for not making the question more clear.

If we have i.e. FRP slab which is 1m long, lets say that first half is 5 mm and second one 8 mm thickess. NEi Fusion that comes with SolidWorks does not allow to define slab as a whole as one part since we have two different thicknesses therefore two different material properties. Instead of that, the only solution I found is represent it as an assembly that consists of two parts defined as shells.

This approach is not problem in case of slab, however my geometry is rather complex and I found great difficulty connecting the NASTRAN mesh between "parts" that would perfectly be aligned for case where actual part is represented as a whole.

 

[adfergusson]

Do you mean NEi Fusion? The issues you are talking about are largely pre-processing issues, not solver (i.e. Nastran) issues.

Most pre-processing for Nastran is done with Femap or Patran and there are also specialist tools to help with pre/post processing work with composite laminates (e.g. we use Laminate Tools). I'd guess that most people reading posts in this group will be such users and won't be familiar with the comparative limitations of Fusion/Nastran-in-CAD. For example, a capability that would typically be used by femap/patran/nastran users to help with pre/post of composite laminates is the global ply concept (youtube has videos outlining what this is in case you haven't come across it yet). However, I don't know whether Fusion's preprocessor can define global plies and/or whether the Nastran solvers built into Fusion have had the capability to use them stripped out.

Anyway, you might have better luck posting on a forum/group for Nastran-in-CAD (same thing as Fusion , but rebadged and updated now that NEi are part of Autodesk) to see if it offers the ability to use things like global plies .