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Turn second layer og twi-axial fiberglass
Posted: Sat Mar 25, 2023 12:58 pm
by FredK
Hello,
I have bought this fiberglass Tri-axial (750gms/226oz – 625mm wide)
I wonder if I put them identically above and below the woodcore? Or whether the above should be turned in some direction. And possibly which one?
Thanks
Fred
Re: Turn second layer og twi-axial fiberglass
Posted: Tue Apr 04, 2023 9:13 pm
by chrismp
The triaxial glass should ideally be used wirthe the same type of fibers facing the core - either the 45 or the 0 fibers. Which one of them is up to you. Placing the 0 degree fibers facing the core results in a slightly softer board over the length with more torsional stiffness. If placing the 45 degress fibers facing the core, it's the other way around.
Re: Turn second layer og twi-axial fiberglass
Posted: Fri Apr 28, 2023 7:57 am
by FredK
Thank you!
Re: Turn second layer og twi-axial fiberglass
Posted: Wed Aug 23, 2023 7:18 am
by SleepingAwake
I'd like to add that from a mechanical point of view it is best to have the 45° layer facing the core. The biax layers have a lower apparent stiffness in the main direction of the core, which will result in less shear stress at the bonding interface between core and laminate and help with longevity.
May or may not be important with your material combo, but won't hurt...
Re: Turn second layer og twi-axial fiberglass
Posted: Sat Aug 26, 2023 11:36 pm
by TimW
SleepingAwake wrote: ↑Wed Aug 23, 2023 7:18 am
I'd like to add that from a mechanical point of view it is best to have the 45° layer facing the core. The biax layers have a lower apparent stiffness in the main direction of the core, which will result in less shear stress at the bonding interface between core and laminate and help with longevity.
May or may not be important with your material combo, but won't hurt...
That's a common misconception. Any gradient of the in plane stress in the complete laminate will result in a shear stress to the core. If your 0 degree layer is on the outside, the shear stress will still be transferred to the 45 and then through the 45 to the core.
I'd put the 45s on the outside. Gives you an increase in torsional stiffness for free.