Apr 022016
 

Doing a bit more searching, previously I had stumbled across one article by Bike Magazine Australia entitled “Lifting The Lid”.

I did try to get in touch with the author via the email link on the website, but heard nothing. However, it appears, that article is a reprint of this article , which was published by Bicycling magazine in June 2013. I thought it might’ve been older than that.

There’s also a furious rebuttal by the Bicycle Helmet Safety Institute. Well lets face it, being provocative helps magazines sell sometimes, although it pays to not be too provocative.

However, I feel the author has a point, even if he gets some details wrong.

It appears that the AIM system mentioned in the article is still in its prototype stage. I doubt this one is royalty free, but for sure it’ll be one to watch, owing to its safety features, and the fact that it’s a very different construction, should make for a cooler helmet to wear in summer.

Apr 022016
 

My father just spotted this television program segment regarding the safety of motorcycle clothing, in relation to thermal management .

They tested two factors, one was how well the clothing managed the wearer’s temperature, and also how well they protected the wearer. Interestingly, there is no Australian Standard regarding protective gear other than the helmet. Gear sold here typically comes with tags citing the CE standard.

Apparently, a lot of gear out there is not fit for purpose, with the more popular clothing being totally inappropriate in our hotter climate, and materials like “ballistic nylon do very poorly for abrasion protection (leather and denim do better). The poor thermal management contributes to heat stress, and the poor design decisions sometimes leave the wearer with a false sense of security.

I suppose it’s worth pointing out what I look like when I go out on the road. This is me wheeling the bike out one afternoon to head home from work.

That’s a cheapo $60 motorcycle helmet (I have never trusted bicycle helmets), and fairly lightweight overalls. Not what you want to try out at 60km/hr on a bitumen road, but I feel is a reasonable balance between thermal management, visibility and protectiveness on a bicycle. A MAMIL I am not!

My commute is about an hour, and involves two biggish hills. Yes, I sweat a bit, particularly my head, but when going long distances, I often take short breaks for a minute.

Riding from my home at The Gap in Brisbane’s north west, to Rochedale in the far South East, a journey of about 40km, I’ll typically stop once when I get to South Bank for a drink, then again near Holland Park, then I reach my destination. I’ve done this in the summer heat without issue. Then again, I’ll be riding at maybe 20km/hr most of the time, which requires less concentration. I find I’m still able to think clearly much of the time.

A loss of concentration on a motorcycle could be fatal due to the higher speeds typically involved. Reaction times are crucial there.

Helmets are typically made from expanded polystyrene foam, the same material used in eskys. In the former case, it is chosen because it crushes. In the latter, it’s for its thermal insulation properties. The head radiates the most heat in humans, and so is a prime candidate for thermal management.

It’s factors like this that make me wonder what came of that AIM prototype helmet design mentioned in the ” Lifting the Lid ” article. Being an aluminium honeycomb would make it more like wearing a heat-sink, an interesting concept that ought to make it cooler. Could this be adapted for motorcycles? I guess we’ll have to find out.

Mar 052016
 

So, having done a little research, I’m starting to come up with some criteria about desirable features.

I had contacted the Bicycle Helmet Safety Institute , Randy Swart was able to provide some guidance on this. Specifically, he pointed to some research they did on the slip resistance of the helmet against various surfaces . Apparently this is a contributor to angular rotation inside the skull.

I’m not sure what the exact contribution is here, whether it’s torque applied to the skull and brain (which bigger diameters will also have an impact on) or something else at play.

He also pointed me to Smith Optics and 6D Helmets . The latter link, describes a system very similar to what I saw in the Vicis Zero1. That is, they’re relying on a filament that’s bonded at both ends, one end to the inner liner, the other to the outer shell, that’s permitted to deform and shear to absorb force.

I wonder if 6D Helmets is licensing Vicis’ patent.

The search query, ” coup contrecoup injury helmet ” yielded some interesting articles. Among them, was this article by Dewsnup, King & Olsen. Interestingly, when I try to access that article directly, I get an “IP Address Blocked” message, however, it can be accessed via Google’s cache .

Now, they’re in the business of accident litigation, and here they’re suggesting people take action against the helmet manufacturers. Ignoring that aspect, they link to some intriguing research. One such article being ” A New Biomechanical Predictor for Mild Traumatic Brain Injury “. There, they discuss angular acceleration as being of particular interest and the one that seems to be the least addressed in current designs.

MIPS is focussed on preventing that angular rotation. The Dewsnup, King & Olsen article also makes reference to another system, Angular Impact Mitigation (AIM) , which uses a honeycomb of aluminium that deforms. It’d be more like a heatsink and less an insulator too. Bike Magazine Australia mention some test results in their article ” Lifting the Lid “.

Based on the above, I’m starting to formulate some further ideas.

I had thought of a honeycomb of silicone rubber as an alternative to anything that looked like filaments. The fact that the AIM system uses a honeycomb structure, with a different material, is encouraging.

Either way, there would still need to be some sort of low-resistance shell. A lot of bicycle helmets have a very flimsy, similar to mylar, shell that if removed from the helmet, can be bent with finger-pressure. The purpose is to reduce friction with the road surface when sliding. This only needs hard-bonding at the edge — one of my old helmets uses electrical-style tape to achieve this.

An alternative might be a cloth with perforations, so that it tears away.

Under this, my initial idea of spines might work. The spines would deform on a direct impact and work to slow-down deceleration of the head. In a sliding type accident, when covered with a cloth cover, the cover would get stripped away to reveal the spines, which would then start to bend over, hopefully slowing down the angular deceleration in the process.

Then a traditional foam liner (or maybe an AIM-style one) can do its job.

This will need some analysis, I’m not sure how exactly to go about modelling this, finite element analysis seems the obvious tool and there are a few to choose from. I guess now is time to start reading up on how this stuff works.