Pre-Laminated Carbon ??

[Erwankerauzen]

In this Kiwi newspaper kindly posted by STINGRAY in ETNZ thread you can read:

The quantum leap in rigging and mast manufacturing came with the advent of carbon rigging. The strength that it afforded, via mechanisms such as the righting moment, allowed designers and naval architects to rewrite the rule book. The next big steps are more subtle, however, as Hauser outlines “There are many small advancements taking place at once. For example, TPT (Thin Ply Technology), and pre-laminated carbon, both of which have been a significant gain for us and allowed us to take significant weight out of the tube while keeping the same thickness. We have always had the philosophy that if we stop evolving and innovating then we may as well close the doors.”

While I have a little idea on what is TPT, or pre-peg carbon, when it comes to:

pre-laminated carbon, I feel a bit ignorant.

Is there any good Samaritan carbon freak scientist to bring some light for  the ignorants ???

Thanks in advance

Erwan

 

[pironiero]

tf is TPT?

 

[Erwankerauzen]

What means : Being poor as fuck?

 

[longy]

TPT = thin ply = very thin layers of (mostly carbon) cloth. Enables better control of where laminate strength goes, less 'edge' ridges.

'Pre-laminated' I must guess is just pre-preg materials

 

[pironiero]

What means : Being poor as fuck?

Being very poor

 

[Erwankerauzen]

Sorry Pironiero, Hope it is not Catie Wood who spoiled your 401 k

Thanks Iongy, but according to the way it is mentionned in the article,I don't think "Pre-laminated it similar to "Pre-peg"

When the Kiwis will stop fighting against each other to decide whether Grant is a pimp or a manager, we migh get some insider insight, but in the meantime.. we have to be patient.

Fair Wind

 

[allweather]

I'm no specialist, but this promotional video of a company using the stuff boils it down to not using traditional tows and instead a special way to spread out fibers that results in less voids and hence less weaknesses from how I understand it as a total layman.

 

[Erwankerauzen]

Thks ALLWHEATER,

For this very informative video, It confirms it is NORTH Swisserland  which developed TPT, and I think they have a production site in Poland or Slovakia.

I think the theory behind TPT is from Pr TSAÎ from Stantford University, but I am not sure.

For the prelaminated issue, in the case of a tube, I think it could be the UD parts @ 0° which are laminated separatly in 2 parts and then put together into the mould or around the mandrel with the +/-45° and other 90° plies.

Of course It is just an assumption

Cheers

 

[longy]

I stick to my guess. Trying to mold rigid parts around a mast mandrel sounds like doom & failure. Not only do you forgo a chemical bond, you're trying to drape new cloth around flat/hard edges.

 

[Erwankerauzen]

Of course, you are right, it is very rational and weight effective to use the same epoxy for bonding and laminating at the same time.

But as I could not suss out what is pre laminated, I just send this random assumption....

After some thinking, I imagine it could be the positionning/stacking of thin UD carbon layers, by a machine, in the appropriate directions in order to achieve the best of TPT?

Just another assumption

Cheers

 

[corby]

Thin Ply Technology refers to layers of non woven fiber. Carbon fiber doesn't like draping around sharp corners and intermediate modulus fibers typically used in spars are even less tolerant of sharp corners or stress raisers. Even the weaving process is enough to reduce fiber properties so using using uni directional layers makes sense. Any crimp or wobble in the fiber, or change in direction, or taper change on a mandrel can cause a failure. The failure normally starts on the compression side and looks like a beveled fracture surface through the laminate before the whole structure fails.

TPT enables a structure to be built using various layers at different orientations to give required properties. Each layer must be placed smoothly with no fiber crimp or kinks. Extra layers can be placed at areas of higher stress as required. The laminate design will specify how many layers are required at each orientation. A mast might have the majority of fibers in the axial direction, say 60 - 70 percent at 0 degrees, 20-30 percent helical fibers at 30 or 45 degrees, and 10 per cent at 90 degrees for crush resistance. Of course extra layers can be added at the boom attachment or spreader or hound attachments. TPT enables the best use of carbon fiber properties and that is why we see bicycles made from more layers of lighter weight non woven plies to yield lighter frames with just the right amount of fiber placed as required.

 

[SimonGH]

TPT is a marketing term for unidirectional prepreg.  Not exactly a new concept (aerospace has been using it for decades) but requires a bit more engineering know-how than using quasi-isotropic cloth for thin structures.

Where things get more interesting is where you intentionally design in coupled response.  If you look at the NASA forward swept wing aircraft design, this was only possible using unbalanced laminates that actually twisted when bent...  are there coupling modes in a main mast that would make sense?

As for pre-laminates, there is sometimes a manufacturing reason for doing this, and depending on the thickness of the cured laminate can be quite flexible.  Ultimately you're trying to obtain the best possible result for a given shape / loading.  In helicopter blades there are plenty of "pre laminates" as the resulting structure is pretty complex and several post cure bonds are necessary.  In a professional setting, you can obtain very efficient results.  However quality control is very very critical to good post-cure bonds.