I was reading about a surfboard called “Futue flex”, it uses a quad axial glass fabric for lamination. I understand this means one of each 0, 90, 45 and -45. I have some questions:
1) Would it matter if I used UD 0,90,45,-45 or if I used woven 0,90 and +45,-45. My question how would it differ if I used UD vs woven, I understand that UD has less crimp and less resin rich regions, does it also have any effect on the mechanical properties?
2) If I understand correctly, 0 & 90 are used for longitudinal and transverse stresses, what are ±45 used for?
If quadaxial lamination common practice for surfboards?
A very smart guy who used to post around here did some qualitative testing of various laminate schedules to include the use of Innegra along with various fiberglass weave orientations. If I recall correctly, he posted a chart that indicated a fairly substantial advantage to ‘backing up’ a normal 90 degree weave cloth with a 45 degree weave. I believe in his testing that the addition of the additional weave direction sort of ‘filled in’ the gaps between strands that are left when using a straight 90 degree fabric. His destructive testing process proved this to be the case.
If you do a search for Benjamin Thompson you might still be able to find some of his stuff. He also did some interesting research on flex analysis.
In answer to question #3: no, quadaxial lamination is not common practice in the industry.
This is not because it isn’t a good idea, but rather because user-friendly fabrics have not been available until very recently (meaning narrow rolls of glass with +/- 45 orientation in ~4 oz. weight and that are stitched so the fibers don’t twist and move around as soon as you touch it).
1 - woven fabrics are easier to drape on a surfboard contour. 2 layers are easier to work with than 4 layers. differences in mechanical properties will be a small factor for a surfboard.
2 - 45’s will stiffen the ‘twist’
3 - common practice is just 0/90 farbic with more fibers in the 0 than the 90 (this is called ‘warp’)