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rhcp89
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Hello, I'm studying on technical university and my job is to project (to model) the way the carbon fiber has to be put in mould which will be the negative of car body. In brief, my work will be used to create a body of a car of composites. The problem is that the car body must be made of aerodynamic ,continuous shapes (no low-radius edges) so when the composite will be put then the unwanted folds may appear or that fiber will have to be cut in some places. I have no such an opportunity to make mould first and then put fiber on it as a test and given this, determine the way the templates should look like experimentally . I have to do it the other way round- I have to predict the shape of these templates given the 3d cad model of car body first. So I would like to know are there any books, articles, methods etc, which tell how to cut that carbon templates for a given surface? Maybe there some graphics which say how to determine the shape of these templates or software(I could import 3d model there)? Thank you, 
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asmasm
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My round about way to do it has been to create clean/low distortion UVs for the models and use them as a template for the cloth shape.
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brainfart
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> I have to predict the shape of these templates given the 3d cad model of car body first.
This has been a problem for hundreds of years, think cartographers trying a projection of a round planet on a flat map without too much distortion. In your case, zero distortion on a body with complicated compound curves.
You can use the CAD software to determine the length of surface lines, the middle of a part (your zero) and several polar coordinates and determine the absolute minimum size of fabrics based on this data.
The cheapest way for good cutting patterns is an existing mold and newspapers, the most exact is probably some cheap glass cloth (twill or satin weave) laid into the mold and then stabilized with some tape.
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rhcp89
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Hello,
What do you mean by UVs? And What does it that UVs are clean?
I know that I can do templates that has low distortion(almost flat) but when there's opportunity to use 1 bigger cloth shape (instead of a few smaller ones), I think it's better because then the whole construction is simpler- and it is important for me , because I have to do finite element analysis (FEA) for that - Such analysis is more accurate when the model is simpler
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rhcp89
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>Brainfart,
"You can use the CAD software to determine the length of surface lines, the middle of a part (your zero) and several polar coordinates and determine the absolute minimum size of fabrics based on this data."
I dont understand why should I determine the absolute minimum size of fabric. In fact I want to use the biggest piece of fabric until there appear first distortions.
"The cheapest way for good cutting patterns is an existing mold and newspapers, the most exact is probably some cheap glass cloth (twill or satin weave) laid into the mold and then stabilized with some tape."
I dont have such an opportunity to use an existing mould. I have to do it theoretically, on computer that well that can be used in reality later.
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brainfart
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"You can use the CAD software to determine the length of surface lines, the middle of a part (your zero) and several polar coordinates and determine the absolute minimum size of fabrics based on this data."
This will only tell you the size your fabric needs to be, and the rough shape of the fabric. Whether or not this can be laid into the mold without having to cut it, well that's another question.
Then again twill or better yet satin weave can be "massaged" into almost any desired shape with a some patience.
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rhcp89
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>Brainfart,
". Whether or not this can be laid into the mold without having to cut it, well that's another question."
I have to know where such cuts may appear if they are proportionally big to the size of the piece of fabric. It is so because such cuts significantly weaken the whole construction(it is not simple car body ,it is monocoque) - I mean its mechanical strength. And I have to do mechanical finite element analysis (FEA). I think I if want to get a valid one ,I 'll have to know quite well where such bigger cuts will appear.
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scottracing
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what cad software are you using? in catia you can flatten a compex curved surface using the applicable toolbar. Otherwise its quite a complex way to create a ply shape as they are always cut on 2d table cutters. Plus when laying up by hand if you have no ply kit then you use masking tape and card to produce templates to cut the carbon in the correct orientation.
I would see what software you can get hold of but Catia and Fibersim are the two mainly used softwares used.
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rhcp89
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Hi My main cad software I use is Solid Edge ST6, but I also have Creo 2(I know it at the basic level) and from tomorrow I probably will be having Solidworks 2014/15- I have never had any hands on experience with that. What do you mean that Catia can flatten the curved surface? (a bowl as an reference to my car body)  1.Is it:  - curved surface is represented by triangles, and then is converted to:  -so we have a net as flat surface 2.or:  -the bowl is laid up with a plain weave fiber, so touches the curvature of a bowl just fine except for this one big wrinkle. I would model this fiber in Catia or other CAD program as a surface of that bowl with one long cut(it would replace that big wrinkle) And then:  -this the flat surface after the bowl was removed. So of course I would like to get a flat surface as 2nd example.Simple I dont want any net. Does Catia can do something like that?
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brainfart
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If you had used twill or satin weave instead of plain weave you wouldn't need to cut. Just saying.
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