Term for the basic multi-directional stitched-together layers of NCF?

[RPstress]

These days non-crimp fabric seems to come in biaxial (+-45 or 0/90), triaxial (A&P does 0/+-60) or quadriaxial forms. What is the best term for this building block of material(s) that are stitched together? Googling doesn't yield any definitive suggestions that I've found; is there someone out there who's dealt with this issue when designing with NCF?

 

[Compositepro]

It is still non-crimp (or stitched) fabric, and is identified by its layer orientations, just as you have done. You simply have more layers.

 

[SWComposites]

Pre-plied stacks?

NCF is essentially the same as uni tape in form once cured. Slightly different properties.

 

[RPstress]

'Pre-plied stack' isn't one that had occurred to us.

When dealing with RFId NCF in two-layer pre-plied stacks we found some quite poor properties, often less than a 5HS cloth. This was put down to the distortion added by the stitching.

 

[berkshire]

The stuff used to just be called stitched reinforcing. You had to specify biaxial (+-45 or 0/90), triaxial ( 0/+-60) or quadriaxial forms.
Nowadays people like A&P are wanting to get fancy with names like QISO, or Bimax, or ZERO.
I like SWs Name of "Pre plied stacks" , That may be more appropriate in pre-preg's. But I do not know about dry fabric.
B.E.

You are judged not by what you know, but by what you can do.

 

[RPstress]

Stitching prepreg is very hard to do. You can do it but it's messy and often needs very high performance stitching fiber or the friction from the B-staged resin breaks it (QinetiQ used PBO for this a few years back—about the highest strength per diameter for a stitchable thread). We liked to use dry fiber NCF and RFI to take advantage of the usual reasons to save money vs. prepreg. We never got around to enhancing toughness by modifying the resin with a thermoplastic veil or powdered TP but it had the possibility to do so pretty easily.

It was always a problem to say something like "To make a quasi-isotropic laminate we need at least four somethings of a two-layer NCF making total thickness a multiple of X." Hmm. "To make a quasi-isotropic laminate we will need at least four pre-plied stacks of a two-layer NCF making a total thickness a minimum of X" works but lacks a certain euphony...