Carbon Fiber Material Properties 1

[Loganrb]

Hey guys, I'm a mechanical engineering that is currently working on my senior design project. I am trying to run some FEA tests in SolidWorks, but have been unable to due to material properties.

I am trying to use a carbon fiber material that is hyperelastic. I was just curious if you guys had any idea what the material properties are for carbon fiber. I am trying to use two different programs for this. Below is a picture of what I'd need for SolidWorks and the other is in ANSYS. Either one would work!

or

 

[RichardEPrince]

There are many types of carbon fiber, based on their manufacturing. The link below gives an overview:

Japan Carbon Fiber Manufacturers Association

The following manufacturers will get you specific fiber properties:

The world's leading carbon fiber producers currently (2009) are:
1. Cytec Industries
2. Hexcel Corporation
3. Mitsubishi Rayon Co., Ltd.
4. SGL Group
5. TohoTenax (Teijin Limited)
6. Toray Industries
7. Zoltek Companies
(From Oak Ridge National Laboratory)

 

[RPstress]

Are you sure that hyperelastic elements are appropriate to carbon/epoxy or similar? Unless loaded with the matrix in a lot of shear the behaviour is very linear, although the compression behaviour may be a bit different from the tensile. Even when the resin is carrying a lot of shear and the load/extension is quite nonlinear it is not elastic, as the resin is being permanently deformed. If you have an elastomeric matrix it would be different for any loading not taken chiefly by the fibres, or for short fibre composites, but I’d expect a more complicated load/extension behaviour for hyperelastic analysis (I'm not an expert in this though).

The screen with the metric density is right for Hexcel AS4C fibre alone, with no matrix. With a polymer matrix it should be nearer 1560 kg/m^3. The density on the US customary screen is for steel. The other US customary values don’t make much sense to me; that’s a high E1 and a high G12 (I can get these values from UHM such as Cytec K-1100/epoxy with 50% fibres at ±45° and 25% at 0°, but there are a lot of variables) and that nu looks about right for 100% any UD at 0°. The thermal expansion coefficient is about right for austenitic steel.

Thanks for that

http://www.carbonfiber.gr.jp/english/

link, RichardEPrince. New to me and quite a good summary. No obvious quibbles from me, although the steel's specific strength looks a little low for a good aerospace alloy (specific props for high-end Ti and low- and high-alloy steel are about the same with more-or-less adequate toughness), but not by much. Also, the composite properties are typically for unidirectional fibres, so beware of cloth.

To answer the specific question, for simple rough FE, to a reasonable first approximation for basic UD,

typical UD HS carbon/polymer material

E11 135 GPa E11t 150 GPa E11c 120 GPa
E22 8000 MPa
G12 4000 MPa (low strain only)
Nu12 0.35


typical UD IM fibre/polymer

E11 155 GPa E11t 175 GPa E11c 135 GPa


Unless you're worried about matrix shear properties these will be linear to failure (more approximate vals than stiffness) at (no damage) 2% strain tension or 1.5% strain compression (if you're lucky). With sensible levels of BVID-type damage these failure strains will be nearer 0.5% for thickish laminates. More capable resins will increase the 'with-damage' values a bit, but they're pretty rough anyway. If failure loads are important then you need to get some fairly specific info, possibly from the NCAMP info at

http://www.niar.wichita.edu/

or more specifically something like

http://www.niar.wichita.edu/ncamppo...rMaterialSpecification/tabid/141/Default.aspx

(registration needed) or similar. The basic properties from MIL-HDBK-17 are still useful.

http://snap.lbl.gov/pub/bscw.cgi/98090

seems to still work.


For woven E11 = 0.45*UD value, E22 = E11, G12 = 3500 to 4000 MPa, nu12 = 0.025 to 0.05.


The strength values you’ve put in imply some sort of laminate allowable, but without some idea of what failure it’s based on I can’t say more.


Tell us a bit more about the lamoinate you're interested in modelling and we may be able to help a bit more.

 

[jjamali]

You can try CES. Cambridge engineers selector software. I looked at that and for a high modulus carbon fibre (diameter=5micrometer) I found:
E 370-390 GPa
Compressive strength 2.2e3-5.2e3 MPa
...