Faserwerk Declares ‘Rockstock’ Carbon Bars with Viscoelastic Damping
Faserwerk integrates a viscoelastic damping layer into the Rockstock carbon handlebar that reduces vibrations by a big quantity. The 189g gentle, 800mm vast handelbar withstands essentially the most stringent testing.
Faserwerk is a brand new element model of kreuz+quer, the corporate behind bike model ARC8 and bicycle.engineering. Because of an funding in a producing facility in Taiwan, we’re in full management over all points of the product, be it design, layup, manufacturing course of, high quality management or testing. The primary MTB product to return out of our new facility is the Rockstock handlebar.
The Rockstock shouldn’t be solely our first handlebar, however the first carbon handlebar in the marketplace to include a viscoelastic layer, lowering vibrations. However let us take a look at the Rockstock’s numbers first:
• 800mm vast
• 20mm rise
• 9° again sweep
• 6° up sweep
• 31.8mm clamp diameter
• 189 grams
• 199 CHF/EUR/USD
We expect that isn’t dangerous in any respect, earlier than even speaking concerning the damping function.
Earlier than we will get into the fascinating world of layup improvement and damping, we have now to speak concerning the design. Design of a handlebar appears straightforward, however it’s not. We went for six° up sweep and 9° again sweep as a result of that feels essentially the most pure with handlebars solely getting wider. 800mm appears the cheap higher restrict, however there’s sufficient area for the controls to chop it down do 740 mm.
We examined numerous totally different designs, and there have been two constant findings in all that testing: Having a easy transition from the 22.2 mm diameter on the grips to the stem clamping are is vital for a light-weight and robust handlebar. And we principally couldn’t discover a bonus in utilizing a 35mm clamp. 31.8 mm would find yourself being lighter and stronger, and we couldn’t discover anybody wishing for a stiffer carbon handlebar. So handlebar design might look quite simple, however as testing of different designs confirmed, it’s nonetheless a key aspect for a excessive perfomance product.
Layup improvement began with a easy FEA, finished in Femap. Utilizing a continuing wall thickness, we will establish stress distribution and main stress instructions.
Primarily based on this, we will begin designing our laminate ply by ply in Laminate Instruments.
For every ply, we see distortions of the ply we have now to anticipate when wrapping it across the mandrel, ensuing fiber instructions and warnings if there are areas with an excessive amount of distortion, which might end in wrinkles or gaps in between fibers. This is dependent upon the place you begin to apply your ply and during which sequence you wrap it, so we will set that in Laminate Instruments. Additionally, if we pressure a reinforcement to comply with a sure path, Laminate Instruments permits us to simulate that, as you’ll be able to see in th image beneath. Such simulations wouldn’t be potential in FEA with out a draping simulation software program like Laminate Instruments.
After we have now constructed the layup, we will analyze totally different points of it, like complete weight, variety of plies, thickness distribution or what fiber instructions are current at a sure location of the product.
This layup can then be straight simulated in FEA, with numerous instruments to look into the outcomes a standard FEA couldn’t supply. The reserve issue plot rapidly exhibits how far we’re from an applicable energy.
Navigating to a component that fails and making a stress/failure index plot by means of the laminate there exhibits us which layers carry load, and which layers fail. That’s not essentially the identical, as a layer that doesn’t carry numerous load can nonetheless fail resulting from an unsuitable fiber course. It’s also extra info than we will get from testing on an precise product. So if we have now a failure in testing, going again to Laminate Instruments helps us to raised perceive the failure.
After figuring out the rationale for failure, modifying the layup and simulating it’s finished inside minutes, an unlimited distinction in comparison with the hours of labor to create a brand new actual pattern. In order spectacular because the precise numbers of the Rockstock are, it solely took 3 iterations of prototypes to get there.
With regards to carbon bars, there was all the time one speaking level: a scarcity of consolation. Because of this began to look into choices to extend damping. We examined varied supplies and strategies. Lastly we discovered one which considerably will increase damping with out lessening the energy and solely including 5 grams in weight. A viscoelastic layer is embedded within the laminate.
How does a viscoelastic layer work?
As with all damping, a viscoelastic layer transforms kinetic vitality into warmth. To go extra into element, when the laminate deforms beneath load, interlaminar shear deforms the viscoelastic layer. As an alternative of bouncing again like an undamped spring, inside friction transfoms this work into warmth. So we needed to establish areas with excessive interlaminar shear to make greatest use of the damping materials. Fortunately, that was straightforward since we already had the FEA mannequin the place we might establish these areas.
So, how does that translate to what the Rockstock makes totally different than a carbon bar with out viscoelastic damping? In case you hit one thing, your handlebar deflects and bounces again. With out damping, it will now hold swinging ceaselessly. Fortunately, there’s pure damping in a carbon handlebar. With the viscoelastic layer, we achieved double that damping. Whereas double might sound like double nearly as good, the precise impact is way greater. Have a look at the diagram beneath which exhibits the response to an influence. With viscoelasic damping (black curve), the vibrations brought on by the influence have principally died off 0.3 seconds after the influence, whereas the pattern purely made by carbon (pink curve) remains to be visibly swinging after one second.
Enhanced Management Over Your Bike
Now that we went by means of the physics of damping, what does that imply to your using? Think about you hit one thing actually laborious whereas using. Your handlebar will deflect considerably, greater than 20 mm in our influence testing. Which is sweet, as a result of a) it smooths out your trip and b) it means your handlebar doesn’t break. However what follows is much less ideally suited: with out damping, your handlebar retains wobbling for a while. A wobbling stick between your arms and your bike is actually not what you need. So the sooner we will cease it from wobbling, the extra exact you’ll be able to deal with your bike. Bear in mind the diagram above: With viscoelastic damping, the wobbling principally disappeared inside 0.3 seconds. With out it’s nonetheless wobbling one second after influence. If you’re using at 36 km/h meaning you lined 10 m of path with lower than ideally suited management of your bike.
Consolation and Well being
Extreme vibrations could cause discomfort and even accidents, as Lewis Kirkwood significantly defined in this interview. Placing your hand on the handlebar will add damping equally to what our viscoelastic layer does, however what does that imply? Your physique wants to soak up the vitality saved within the handlebar. This could result in results like arm pump, diminished grip energy, numbness or inflammations. So by including damping into your handlebar, your using will get extra gratifying, and you are able to do that additional run whereas your folks want to provide their arms a relaxation.
ISO doesn’t specify any influence testing for a MTB handlebar, which appears fairly irresponsible. There’s nonetheless a take a look at for BMX, the place a weight of 10 kg drops from 500 mm top onto one finish of the handlebar. That’s fairly a stringent take a look at, however with the Rockstock, we handed double that requirement regardless of the handlebar solely weighing 189 grams.
The Rockstock is in inventory and may be bought by means of the ARC8 website or chosen sellers.