revtothelimit - motorbike forum

Ok, it's an American 'football' helmet.

However, it's radically different to the typical rigid expanded polystyrene form liners in motorcycle helmets and is designed to mitigate against both linear and rotational forces.

Lots of inpact animations etc:

https://rheonlabs.com/rheon-technology- ... shadow-xr/

https://rheonlabs.com/rheon-technology- ... shadow-xr/

Ummmm i'm going to need convincing.

Makes some kind of sense for sure....first couple of Qs though (I've not read it in detail).

What happends if you get a point impact between the cells? You're essentially relying on teh stiffness of the shell to transmit the load out 'sideways'. I suppose you don't really get sharp edged impacts in American Football.

Do the cells need to remain stuck/glued in the right place? Will they move over time?

weeksy wrote: Fri Jan 21, 2022 8:07 am


Ummmm i'm going to need convincing.

Sorted



Although it might need a change of bike.

And lifestyle
And recreational substances
And music choices

Mr. Dazzle wrote: Fri Jan 21, 2022 8:10 am
What happends if you get a point impact between the cells? You're essentially relying on teh stiffness of the shell to transmit the load out 'sideways'. I suppose you don't really get sharp edged impacts in American Football.

Dunno. It appears somewhere between current bicycle and motorcycle helmets.

For motorcycles, there's the DOT Vs ECE argument. Which DOT are gradually giving up.

Mr. Dazzle wrote: Fri Jan 21, 2022 8:10 am Do the cells need to remain stuck/glued in the right place? Will they move over time?

Dunno.

Something must hold them there

But your Q made me wonder about the effects over time on current rigid foam from slight shell movement/flex? Does the foam gradually and slightly compress away from the shell?

weeksy wrote: Fri Jan 21, 2022 8:07 am


Ummmm i'm going to need convincing.

Needs more orange?

I think current helmets have an intermediate layer between the shell and the polystyrene? I.e. theres something to "absorb" the mismatch. I'd kind of expect them to squeak if there wasn't!

Mr. Dazzle wrote: Fri Jan 21, 2022 9:09 am I think current helmets have an intermediate layer between the shell and the polystyrene? I.e. theres something to "absorb" the mismatch. I'd kind of expect them to squeak if there wasn't!

I don't remember older lids squeaking.

Are you thinking of 'slippy' inserts to mitigate against rotational forces?

Could the hexagonal columns allow for rotational forces? (Genuine question)

dayglo jim wrote: Fri Jan 21, 2022 2:13 pm Could the hexagonal columns allow for rotational forces? (Genuine question)

Watch the video on the links. The columns sway like hula dancers. Ok that may be an artistic exaggeration.

Mr. Dazzle wrote: Fri Jan 21, 2022 8:10 am Makes some kind of sense for sure....first couple of Qs though (I've not read it in detail).

What happends if you get a point impact between the cells? You're essentially relying on teh stiffness of the shell to transmit the load out 'sideways'. I suppose you don't really get sharp edged impacts in American Football.

Do the cells need to remain stuck/glued in the right place? Will they move over time?

Doesn't happen in real life crashes either, unless you are unfortunate enough to be Ayrton Senna. If you bash your head on the road, it's an impact on
a flat surface. You may hit a kerb or perhaps the roof line of a car, in which case it's an 'edge' impact. It's one of the criticisms of the Snell test that the helmet is over-tough to prevent penetration by sharp objects.

The injury that conventional helmets don't protect well against are due to 'twisting' impacts which spins the skull inside the helmet - the brain takes a moment to catch up and tears various bits and pieces.

I assume that that inner has to be anchored to the outer or it wouldn't deform under twist.

I presume American football helmets are designed to cope with repeated, frequent, *relatively* small hits. I think there's growing realisation that even quite small shocks, if they happen often enough, can cause brain damage. I think there's even been a class action and settlement of compensation for NFL players. And the issue even seems to extend to rugby and football. Tackles in rugby and headers in football - I read an interview with Peter Crouch recently in which he said he was quite worried about getting dementia because he's probably headed the ball more often during his career than almost any other top player.

Most of us, I assume ( ), don't experience the same type and number of shocks to the head that these sportsmen do, so maybe helmet design needs to be different?

Scootabout wrote: Sat Jan 29, 2022 10:38 pm I presume American football helmets are designed to cope with repeated, frequent, *relatively* small hits. I think there's growing realisation that even quite small shocks, if they happen often enough, can cause brain damage. I think there's even been a class action and settlement of compensation for NFL players. And the issue even seems to extend to rugby and football. Tackles in rugby and headers in football - I read an interview with Peter Crouch recently in which he said he was quite worried about getting dementia because he's probably headed the ball more often during his career than almost any other top player.

Most of us, I assume ( ), don't experience the same type and number of shocks to the head that these sportsmen do, so maybe helmet design needs to be different?

American football is probably somewhere near boxing on an equivalence chart in terms of impact, since the protection given to the 'deliverer' of the blow made helmet to helmet possible and they were hard impacts. These impacts were legal until just a few years ago and it wasn't uncommon to see a player knocked out. There are many anecdotes of players who were knocked out returning to the game and behaving erratically. Longer term, there were a number of players who were suspected to have been badly affected by repeated impacts. Junior Seau, who played between 1990 and 2009 and was one of the best players of his generation, but committed suicide at the age of 43 - to quote Wikipedia, studies by the National Institutes of Health (NIH) concluded that Seau suffered from chronic traumatic encephalopathy (CTE), a disease that has also been found in other deceased former NFL players. It is believed to be caused by repetitive head trauma, and can lead to conditions like dementia, rage, and depression

Using the helmet to deliver an impact to another player is now banned and heavily penalised (and could lead to heavy post-match fines too), and now almost ANY impact to the head draws a penalty in the game. The NFL has also instigated very strict head injury protocols with plays where there is potentially head impact reviewed by independent observers via the TV footage and players pulled from the game for assessment if there is a suspicion that they might be concussed.

Heading in youth football is now banned, and there has been talk of banning heading in the Premiership. Naturally there are those who think it will turn it into glorified 5-a-side soccer, but concern is now widespread.

Having said all that, I suspect that the repetitive shock aspect is unlikely to be a concern for the average road rider - I have almost certainly suffered concussion once through a bike crash - though it could be for a racer, who is much more likely to fall off and suffer a bang to the bonce.

FWIW, I was more interested in the construction & materials aspects, that it is dramatically different to the rigid expanded polystyrene foam typically used in motorcycle helmets.


I've posted before about UCL research ( a few years ago, no idea what they're up to now) into traumatic brain injury.

NFL was used as there's multi-camera recording of impacts, used to create computer simulations) and extensive high quality medical investigations (used to validate the models). The intention was to develop predictive pre-hospital systems guided by in-vehicle sensors.

They were also investigating how neck movement might reduce the effects of head impact injury.


PS they were also funded by a major clothing manufacturer on work relating to airbag technology - but were reluctant to discuss

https://rheonlabs.com/rheon-technology- ... atlas-4-0/

More info, being used in the new Ruroc helmet.

Interesting. It might have been on TRC or elsewhere but i remember reading about manufacturers looking at shear plastics, when they were being used more for body armour, but the potential weight was an issue (although it would have made a smaller helmet shape and profile). Things have moved on.

Seems odd that they'd go to so much trouble to mitigate against injuries caused by rotational forces and then stick a bull bar on the front that looks like it was designed to catch on stuff and twist the head on impact.

I thought the rotational stuff had been dealt with by the MIPS system?

https://mipsprotection.com/moto

lostboy wrote: Fri Mar 25, 2022 10:18 am I thought the rotational stuff had been dealt with by the MIPS system?

https://mipsprotection.com/moto

From brief chat with someone who knows more than I do, this new liner is also far better at impact absorption than the current polystyrene foams. MIPS adds some rotational mitigation, but still relies on the foam.

The 4.0 isn't listed on Sharp yet.