Impact Speed

[benb]

Both. A split helmet has failed to absorb the amount of energy that it is designed to. A split helmet in the hands of someone who has just come off their bike wearing it looks like it saved them from a broken skull for sure, unless they know better.

Or, the energy was greater than the helmet's design parameters.

 

[benb]

you did explain one way it might be possible, its important for people to realise it is not certain.

So in short, a helmet may scratch which will protect the head from scratching and in other cases the helmet may scratch when the head wouldn't have scratched. In both cases the head didnt scratch so it confirms the helmet has done its job (as far as stopping scratches)

Haha, brilliant! I have a key ring that repels bears. Well, I've never seen a bear nearby so it must be working!

 

[srw]

The notion that somebody who wears a helmet is boring shows everyone your own ignorance

She's already said she's quite fond of someone who regularly wears one (as it would be trivially easy for you to find out).

 

[Licramite]

"a force of 73 Newtons is enough to cause a simple fracture, this
force is the equivalent of walking into something solid. An
unrestrained adult fall from standing has been shown to produce a
minimal force of 873 N which is more than enough to produce a skull
fracture."
1N = 9.812 Kg m/s/s , so 70kg @ 1km/p/h = 1.98Newtons - ? (methinks) (he of cse grade 3 maths)

and that is calculated against the frontal lobe the temperal and rear are thinner so we are looking at under 73 newtons.
assuming my calc is right we need a speed of 36.8Km/p/h or 22mph. to get into the fractured skull range.
that ties up nicely with the G force of 16G - so not only do you take brain damage you fracture your skull.

 

[theclaud]

The post didnt talk about helmet evangelists, so why bring that up, oh yes once again its to try to justify your responses which are out of context.

Any post that goes close to suggesting a helmet may bring the smallest amount of benefit is jumped on quickly. I merely summarised somebody elses point and your fear makes you jump on it and become personal, very poor form.

The notion that somebody who wears a helmet is boring shows everyone your own ignorance

YAWN! Some of my favourite people wear lids. Luckily they don't go ON AND ON at people who don't.

 

[Twilkes]

"Ohhhhhhhhh, oh-ohhhhhhh-oh-ohhhhhh, oh-ohhh-ohhh, Li-cra-mite" - that's the song I've got in my head now.

I would add that part of the way helmets (are meant to) work is to dissipate the energy around the head. So if you hit someone's head with a hammer, there wcould be 1 made-up-force-unit hitting you across an area of about 1 square centimetre. But if you were wearing a bicycle helmet this 1 made-up-force-unit would/could/should be dissipated across the area of the helmet, reducing the force experienced by any particular square centimetre of your head quite significantly.

So it's not all about damage and compression.

 

[david k]

Which part of looking at a small number of photos found by Google does not give valid findings do you not understand?
1) We do not know whether or not those photos represent a normal spread of damage types. It may be that people are more likely to photoand publish a dramatic split. We can be reasonably sure that people are not likely to take photos of no damage at al.
2) The number is too small to draw conclusions from.

I do understand quite clearly, it was you who made all the assumptions and then wouldnt answer why
when you thought it supported your agenda you step away
I questioned it to show you how ridiculous it is to use this as evidence against helmets, it doesnt prove anything one way or the other but you bring it up as evidence, clutching at straws or what

and despite you trying to claim you never told me to f off you clearly did

 

[david k]

Haha, brilliant! I have a key ring that repels bears. Well, I've never seen a bear nearby so it must be working!

ben, your missing the point, im pointing out how ridiclous the claims are, they do not prove that helmets dont work (they also dont prove they do) but it was presented as evidence against helmets and as you say Brilliant!

 

[david k]

YAWN! Some of my favourite people wear lids. Luckily they don't go ON AND ON at people who don't.

im glad to hear it, neither do many posters on here, in fact it is the opposite, remember who posted the evidence in the first place

so yawn, yawn, people saying helmets dont work again, please take your own advice and stop going on about it

 

[srw]

I do understand quite clearly

No you don't. Here is the evidence.

it was presented as evidence against helmets

 

[david k]

anyway, so we are all agreed that the 'survey' proved nothing

 

[benb]

ben, your missing the point, im pointing out how ridiclous the claims are, they do not prove that helmets dont work (they also dont prove they do) but it was presented as evidence against helmets and as you say Brilliant!

I'm not missing the point: you claimed that a helmet that had scratched in a situation where the head wouldn't have was effective!

 

[Licramite]

"Ohhhhhhhhh, oh-ohhhhhhh-oh-ohhhhhh, oh-ohhh-ohhh, Li-cra-mite" - that's the song I've got in my head now.

I would add that part of the way helmets (are meant to) work is to dissipate the energy around the head. So if you hit someone's head with a hammer, there wcould be 1 made-up-force-unit hitting you across an area of about 1 square centimetre. But if you were wearing a bicycle helmet this 1 made-up-force-unit would/could/should be dissipated across the area of the helmet, reducing the force experienced by any particular square centimetre of your head quite significantly.

So it's not all about damage and compression.

thats enough to drive you nuts !
I do that when I'm cycling I get a tune and put words to it, other day I found myself puffing up a hill and singing - to the tune of sweet georgie brown
"Know one knows how slow it goes my cheap halfords bike
One good fart it falls apart my cheap halfords bike
The brakes are furked the stearing to , the gears are shot through and through , hell I wouldn't even sell it to a git like , my cheap halfors bike"

I am very sad. - say it son it's good for the sole

yea - 15pounds per inch2 = 73 newtons (apparantly), so yes an impact area of say 4" is going to need a load of 60pds to create the 73newtons,
I'm trying to find out how much force helmet can take before it breaks. - but it's kind of obviouse cases were helmets have broken are more likely to be associated with head injuries as its going to take a hefty lump to break it.
figures for injuries came up with
upper extemities (arms, hands,shoulders) 59.6
lower extremities(legs,feet,hips) 46.9
heads 22.3 = 13.4% of the total injuries.
face 34.8
neck 2.7

so theres lots of other bits that could cop the full force , a femur takes a force of 30newtons to break it , a rib cage is about 73newtons.

 

[Little yellow Brompton]

thats enough to drive you nuts !
I do that when I'm cycling I get a tune and put words to it, other day I found myself puffing up a hill and singing - to the tune of sweet georgie brown
"Know one knows how slow it goes my cheap halfords bike
One good fart it falls apart my cheap halfords bike
The brakes are furked the stearing to , the gears are shot through and through , hell I wouldn't even sell it to a git like , my cheap halfors bike"

I am very sad. - say it son it's good for the sole

yea - 15pounds per inch2 = 73 newtons (apparantly), so yes an impact area of say 4" is going to need a load of 60pds to create the 73newtons,
I'm trying to find out how much force helmet can take before it breaks. - but it's kind of obviouse cases were helmets have broken are more likely to be associated with head injuries as its going to take a hefty lump to break it.
figures for injuries came up with
upper extemities (arms, hands,shoulders) 59.6
lower extremities(legs,feet,hips) 46.9
heads 22.3 = 13.4% of the total injuries.
face 34.8
neck 2.7

so theres lots of other bits that could cop the full force , a femur takes a force of 30newtons to break it , a rib cage is about 73newtons.

I've been sitting here watching your hotpotch of units , with your assumptions and roundings and your fixation on force. Helmets are tested in Joules, a BS helmet is "good if it doesn't shatter under 100J . I'll be interested in watching the mental gymnastics from here.

 

[Little yellow Brompton]

Nooooo

Oh did I let the cat out of the bag, did you want him to slog on with G and Newtons a bit longer?