FEM for composites in SolidWorks

[Jonny_trigonometry]

Anybody know how this is done? I want to do a stress analysis on a wing design, but COSMOSXpress yells at me when I choose to use a composite material.

[TVP45]

I doubt that Xpress will let you do that. What kind of composite?

[PerennialII]

........and what does it actually yell about? Am not really familiar with Cosmos but would think it has the same layered elements as every other general purpose package.

[Jonny_trigonometry]

It doesn't like that "young's modulus isn't defined". How does one do stress analysis on composites anyway?

[TVP45]

When you say composite, what exactly do you mean? There are composites like chopped fiberglass that can be reasonably approximated with isotropic bulk properties. Then there are composites like garolite that have distinctly different properties in different directions - Xpress will not work with those. What sort of composite do you have?

[PerennialII]

So one would need access to CosmosWorks (or whatever the advanced version is called nowadays) for analysis of 'real' composites (which can not approx. using simple isotropic models and such) ... ?

[Jonny_trigonometry]

When you say composite, what exactly do you mean? There are composites like chopped fiberglass that can be reasonably approximated with isotropic bulk properties. Then there are composites like garolite that have distinctly different properties in different directions - Xpress will not work with those. What sort of composite do you have?

hmm. I'm unfamiliar with different types of composites. I'm jumping the gun at this point so far too, because we need to perform cfd first, then we can make a better design for the structure. I will probably have to come back to this thread later when more info is known and understood. As for now, I'll check out the different types of composites. Any ideas on what types are most reasonable? We're looking for something that isn't expensive and isn't hard to work with--can be used in production in a timely and cost effective manner.

[TVP45]

So, I assume you're going to build a real wing? To test or to actually fly? Do you have a shop? Are there safety procedures in place for using nasty chemicals? Do you have some money available? Does anyone have composite experience?

You don't need to answer those now, but should know them when you come back.

[Jonny_trigonometry]

So, I assume you're going to build a real wing? To test or to actually fly? Do you have a shop? Are there safety procedures in place for using nasty chemicals? Do you have some money available? Does anyone have composite experience?

You don't need to answer those now, but should know them when you come back.

I personally won't build anything. I'm just curious because I'd rather help design something that is easy to build, thus lowering production cost and making the design more plausible. I'm on a design team doing a trade study on an existing wing design to see if we can make it better. Obviously, composites is a good thing to investigate, since they are stronger, you can lower the weight of the wing and the amount of structure to support it.

[TVP45]

OK, I understand. Composites is a complicated question. Cost may be quite high and has to be balanced against performance. Is this a full-sized airfoil, i.e., for a commercial plane?

[FredGarvin]

I'm on a design team doing a trade study on an existing wing design to see if we can make it better. Obviously, composites is a good thing to investigate, since they are stronger, you can lower the weight of the wing and the amount of structure to support it.Those are definitely benefits. However, since you are doing a study, make sure that you look into the costs associated with production, which are very large. Things to consider are the costs associated with the purchase and operating a large autoclave. Environmental and operational changes for the use of chemicals not normally associated with standard production methods. These costs are definitely not trivial, especially for a company that wishes to change or add the composite capability to their current ones.

[Jonny_trigonometry]

Duly noted Fred. Thanks for the advice. It seems we might not get into as much of the structures as I was hoping for though, because its taking forever to freeze a design as of now.