0¦/90¦ layup. Is there a difference for a symmetric fabric?
0¦/90¦ layup. Is there a difference for a symmetric fabric?
(OP)
Howdy all,
I'm going to lay up some test panels of carbon fabric with EA9390 adhesive and cut tensile test coupons to compare strength. I'm going to make three panels of 3K-70-PW (8 plies), 3K-135-8H (4 plies) and AH370-5H (4 plies). I was wondering If there is a difference between the 0° and 90° direction for a fabric with the same number of tows per inch in each direction and the same fibers per tow. Should I lay up the panel with all laminae in the same direction? Should I alternate back and forth? If I lay up the panel with all laminae in the 0° direction should the test coupons pull the same if cut in the 0° vs 90° direction?
My intuition is that they should be identical regardless of ply laminate direction and test coupon direction as long as it's parallel to one of the fiber directions, but I wanted to check with this august and knowledgeable forum for their expertise.
Thanks,
-Kirby
I'm going to lay up some test panels of carbon fabric with EA9390 adhesive and cut tensile test coupons to compare strength. I'm going to make three panels of 3K-70-PW (8 plies), 3K-135-8H (4 plies) and AH370-5H (4 plies). I was wondering If there is a difference between the 0° and 90° direction for a fabric with the same number of tows per inch in each direction and the same fibers per tow. Should I lay up the panel with all laminae in the same direction? Should I alternate back and forth? If I lay up the panel with all laminae in the 0° direction should the test coupons pull the same if cut in the 0° vs 90° direction?
My intuition is that they should be identical regardless of ply laminate direction and test coupon direction as long as it's parallel to one of the fiber directions, but I wanted to check with this august and knowledgeable forum for their expertise.
Thanks,
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.





RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?
Rob Stupplebeen
RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?
There are fabrics like 1581 fiberglass that has 66 tows in one direction and 64 in the other (I'm working from memory so I may be off a bit) but for these if there is a variation, it is statistical and not by design. I am not concerned with statistical variation since I would affect both directions the same (well statistically speaking anyway.)
rstupplebeen,
I figure both directions would be equally bent, unless they were tensioned before cure. This might be a good research subject as a matter fact. The one variation that would make a difference is with a Satin fabric you could decide if you want the outer surface fibers to be aligned with the test coupon or across the coupon.
Thanks for both of your responses,
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?
Chris DeArmitt PhD FRSC CChem
www.phantomplastics.com
Consultant to the plastics industry
RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?
O.K. I understand what you are saying, and I agree that the laminate properties would be different off axis. This is a well known property of comosites. But for my test I am only concerned about the properites along the 0° and 90° direction which are parallel to the warp and weft of the fabric.
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?
RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?
All of the satin weave fabrics have a warp-face and a fill-face. These are inherently unbalanced, though not necessarily in AFW. If you cure a single ply it will come-out shaped like a potato chip.A single ply of plain weave can be fairly flat. With unbalanced fabric the plies in the lower half of the layup are flipped-over (not rotated) relative to the upper half.
It gets a little complicated so it is important to understand why you do these things.
RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?
Follow on question,
For say the 8H satin I can have either the warp face out or the weft face out. I can also cut my test coupon along the warp direction, or the weft direction. I'm guessing the coupon would be strongest with the warp direction fibers on the outer faces of the test coupon and aligned with test coupon. Does this sound right?
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
RE: 0¦/90¦ layup. Is there a difference for a symmetric fabric?