Kevlar composites

[biomech]

We are trying to make a composite surface that we can clamp a 2.0-mm wire onto that will be required to carry a transverse load. We are having problems making the surface of our composite hard enough to prohibit the wire from sinking into the surface when we clamp down on it. Does anyone know if a layer of Kevlar will provide us with this increased hardness and what thickness we should use? Or is there some other way that we can increase the surface hardness of our composite we've tried several mesh angles and temperature ranges but with very little success.

Thanks,

Dwight Bronson, MS

 

[PEmrich]

Kevlar will not help surface hardness any more than glass or carbon. Surface indentation hardness will increase with fiber volume fraction but may not get to the level you need. Indentation hardness is more a function of the matrix used. The general rule is that better hardness equals less resin. The alternative to reducing resin by increasing fiber vol fraction is to add fillers to the resin. What properties does your laminate need? What clamping force is used?

 

[biomech]

Thanks PEmrich for your reply.

I looks like we are applying about 600 N of clamping force onto the surface of the carbon composite through the 2.0-mm wire.

Thanks

 

[Padlofski]

Hi,

How about some Boron Fibre in the surface at 90 deg. to the wire?
Boron Fibre at about 0.1mm dia and 400Gpa modulus may act as a bridge across the underlying fibres.
We have some Boron fibre fabric/alligned tape (Boron Warp / Titanium Weft)NOTE: WEAR EYE PROTECTION WHEN CUTTING THIS STUFF

email me direct and i can send you a small peice to try.

My email: composites@btinternet.com

 

[vonlueke]

Transverse usually means across a cross section, so I assume the wire is required to carry a load normal to the surface. Please correct me if I'm wrong and wire is required to carry a load parallel to the surface.

How about installing a metal plate "fixture" consisting of one small, thin, metal base plate on each side of the composite--to create a wire clamping "station," if you will? The two metal plates will be held apart, at a distance equal to the composite plate thickness, by metal sleeves between these two metal base plates. This metal fixture would then resist a very large wire clamping force, all internally, without transmitting (essentially) any clamping force to the composite. Hope this helps.