Thermal Analysis of Composite Material with ANSYS Classic

You have at least two options, either involves smearing the properties. By smear, I mean that you compute the volume percentage of the reinforcing fiber and then create a "synthetic" material where the thermal properties are just the relative percentages of the combination. For example, say that the given thermal property is 1 for the fiber and 0.5 for the material surrounding the fiber. The volume fraction of fiber is 25%. So you get (1 X 0.75) + (0.5 X 0.25) = (0.75) + (0.125) = 0.875. This type of approximation was once used in tire stress analyses. What happens is that typically, the higher property value overwhelms the lower and becomes somewhat independent of the volume fraction.

For option 2, if you wish to get finer approximations, then create a separate solid "layer" that is just cover material and a 90% fiber center section, with another layer of cover.

In either case, the directionality of the composite drops out as the thermal models behave with relatively isotropic behavior in any given layer.

That said, if you wish to to investigate inter-layer shear, then go for the higher level (more parameter) elements

In ansys classic, you can first set, under the main menu, "Preferences" to Thermal.

Now only "thermal" selections appear in Ansys.

In 2d, one could add a 55 or 77 element Quad. (preprocessor -> element type)

In 3d, one could add a 8node brick 70

Under material properties, one could then add a material model, and under "Conductivity", select "Orthotropic".

thanks a lot for answering.

if you are using an old license (up to 5.5 edition),
be aware that using simmetry boundary conditions, you can get surprizing and phisically meaningless results.

If you are working with cilinders better to model it all in a 3D analysis.

good work

The previous comments are quite clear about what to do.

I just would add that if you're confuse about proportions and material behaviour, previously to assemble your analysis model, try to build a small brick with orthotropic properties as you wish, and get a "standard" model from a very simple geometry. Once you mastered your material modelling and material characteristics assignment, then customize a material and go for the real model. I always like to check my models this way before proceeding to the big one.

And - of course - always do some "back of the envelope" calculations with average values. You never know where finite element analysis can end...