http://www.compositeshop.de/unidir.html
I’m curious if it forms well in complex shapes, curves, does it lay well. How is its compatibility with epoxy and VE?
I don’t see what might be and issue with it. It WILL drape, slightly. DO not expect it to be like a fabric…the PES mesh will still keep it pretty well tight. However, depending on your epoxy, and your cure cycle, the PES might melt into the epoxy and act as a toughener 
I use it. Riff is right, it doesn’t drape like fabric. The only issues I have is that the PES prints though (I cure at RT). It also only holds the fibers that it directly contacts. If you wet layup and pull the brush in a different angle to the fibers they will move. Neither is a real problem, though.
Hi Kevin,
Thanks a bunch for your advice, also thanks Riff42.
Well, I have some of that material in house, but I cannot get it to stay on contours, if I put a small amount of spray adhesive, the top fibers stay, but the rest moves. I want to use in infusion but have not yet given it a shot due to the issues in holding it at the right place. The layup where I’m thinking of using this will have multiple plies with a sandwich, and they’ll all get de-bulked easily if they didn’t slide between themselves. In your case it’ll be easier, due to hand layup. Print-thru will be an issue that I’ll need to test.
We sell the stuff in NL. Comes from Epo Faser, now merged into SGL.
The PES binder threads do not dissolve.
I actually did a nice project 2 weeks ago: 15 students learnt to calculate a simple structure, (bridge), calculated a project, made the project, and tested the project. All used the UD fibers in the link.
Great, some questions off the bat related to your project if you can share: Were there any curves that you had-to/could follow, with an axis in bias to the fiber direction. What material properties did you use for the calculations? Was it hand layup, vacuum infused or prepreg’d? What resin system did you use? What did the test entail? Did it break at the predicted level? What fiber vol fraction can you get using this? Did you use the carbon material or the glass?
Another question: the material that I have is in single thickness and in double thickness around (the double is joined together at the PES side, so you have uni on both sides. Have you experience with this, is there a marked difference in usability?
I can understand that PES will not dissolve in resin. Its a tough thermoplastic.
I’ve seen similar material from other suppliers, this one is 300mm in width, the material that I’m planning on testing is 1250mm in width. I was interested in the glass version for its suitability in some antenna fairings. There the curves are a bit pronounced and I’m finding it difficult to follow the curves with this.
For curved areas you could opt for a multiaxial (Selcom, Fregona). I believe Mates is Italian distributor. You could also use a biaxial.
I have no experience with double thickness material. But I do not feel it makes a difference.
As for the project:
-no curves (flat panels)
-I should look up the properties. It was partly sponsored by an engineering firm, they took care of the calculations. However, there is an E-book available on UD properties and how to find or calculate them. (see attachment)
-resin was polyester (I know…)
-test was a very simple 3 point bending.
-failures were skin buckling
-calculations and tests were very similar, my group even managed to be 100% spot on! However they failed to meet the minimum requirements.
-material was wet-bagged without bleeder, and put in an oven.
-Vf for UD can be very high, into the 60s
-we had available: 200 gr carbon, 250 gr glass, woven 200 gr glass, 8mm foam (60kg/m3)
I’ve not been able to get selcom to sell anything to us, for the last 2,5 years perhaps, we’ve not approached the right people. Initially we worked with Saertex then with G-Angeloni, with good success, both have been reliable and material quality from them is quite good. Good to know your parameters. Vf of 0.6 in wet layup is quite high.
Your comments have convinced me to make a test part, and I’m seriously considering that option.
Thats a firehole perspective on material data. The software we use, NEiNASTRAN, plugs the Firehole technology, Helius, for calculations. We actually use properties based on material tests done by our process/materials/products at a NADCAP certified lab and use MIL-HDBK-17-2F techniques for data generation. I was curious about your data since you mentioned a specific experiment with calcs. Would still like to know what you used in calcs.
PES will dissolve if you let soak at 200f, and then ramp up the cure. We have used it many times in 350f epoxies, both prepreg, and infusion. It will act as a toughener. It’s all epoxy and temp dependent…
Riff, I’m going to plan a test with this material in a few days, and will see if this will work. If it acts as a toughener, that would be perfect, although the resin we’ll use is pre-toughened. Thus, my immediate concern is not toughening, but its ability to drape over a curved/curved surface. For instance to build the fairing for a radio antenna.
Well yeah, the uni will not drape as well as a fabric in any case. You can get away with strips, depending on your shape…but not a nice coverage.
What I have is 300mm wide roll. I’m going to do a few layups for the antenna cover in a couple of weeks… What I’m looking for is similar material (spread tow glass with 150-250gm/sqm) but stitched, not glued with PES so it can be set in corners.