Composite Laminations

Composite Laminations

Dear list users,

I am coming in on the tail-end of what seems to have been a very interesting
discussion with regard the inquiry from Lisa on lamination configurations.

My portfolio as director of education for Cascade Learning Center means I
oversee the coarse material for all the seminars that are presented. One of
the seminars is in fact Carbon Composites. Although there is no written data
with regard testing of different lay-up protocols, I can give you an idea of
the in-house testing that we have done and that we base the seminars on.

Carbon on its own has no above average strength qualities. It is the
composition of carbon with other materials plus a resin that gives it the
strength that we talk about. The term I-beam is used often and that is exactly
what we have to produce. The strength of carbon is relative to the distance
that two layers are separated from each other. The most effecient and cost
effective material that we use for this spacer is nylon stockingnette. There
again is no test data to support the following, but through the lamination of
virtually hundreds of sockets between myself and Dan Tatum, previously
director of central fab for Cascade and now owner of Tatum central fab, we
have found the following to be a good protocol:
- 2 carbon layers seperated by 2 nylons is safe up to 120 lbs
- 2 carbon layers seperated by 4 nylons is safe up to 220 lbs
- 2 carbon layers seperated by 6 nylons is safe up to 300 lbs

Now obviously if you have a muscleman that weighs 220 lbs but squats with 250
lbs, then you need to re-think your layup a little. If you are laminating a
3-prong adapter you will have to consider the lay-up at the adapter, etc. The
resin that we have found to impregnate the above composition the best is
acrylic modified apoxy resin or AME as it is commercially known. The trick is
to roll the fibers to truly express the air from the lamination. Do not exceed
4 persent catalyst.

There are many different carbon braids and each have a use but not all work in
our field. I could discuss that forever, however in short, the tubular carbon
braid with a 45 degree orientation of the fibers give us both the compressive
and tensile strength that we require. There are still the stresses and strains
to consider which in a nuttshell is the linear relationship between elongation
and axial forces. (If anyone wants to read up on Hooke's law.)

Carbon composites is in fact listed under the modulus of elasticity or Young's
modulus and this is a table that measures how elastic materials can be before
there is permanent deformation and this is a factor E.

I am sad I missed the discussions to date. There certainly is much more and if
you have any more questions I will gladly answer it if you contact me through
Cascade at 1800 888 0865.

I wish you well over the festive season,

John Hattingh CP