Nuxx:4e30d8d4$0$2488$db0fefd9@news.zen.co.uk

Path: num2.nntp.dca.giganews.com!num1.nntp.dca.giganews.com!number.nntp.dca.giganews.com!border3.nntp.dca.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!goblin1!goblin.stu.neva.ru!feeder.news-service.com!tudelft.nl!txtfeed1.tudelft.nl!dedekind.zen.co.uk!zen.net.uk!hamilton.zen.co.uk!prichard.zen.co.uk.POSTED!not-for-mail Message-ID: <4e30d8d4$0$2488$db0fefd9@news.zen.co.uk> From: Nuxx Bar  Newsgroups: uk.rec.cycling Subject: Re: Saved by her helmet Date: Thu, 28 Jul 2011 04:34:43 +0100 References:       <6q5r27h11g4nsjtkl5opipsclhv9e60f6v@4ax.com>  <35rv279l78i20spgmo7hj26p1vj97oichg@4ax.com>  Lines: 62 User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.7; en-US; rv:1.9.2.18) Gecko/20110616 Thunderbird/3.1.11 MIME-Version: 1.0 In-Reply-To:  Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Organization: Zen Internet NNTP-Posting-Host: c4626a64.news.zen.co.uk X-Trace: DXC=L6c6Z1BcYI3nScXH8;T;I:0g@SS;SF6n7R9OH0:RnEN4\C On 27/07/2011 11:49, Greentable wrote: >> On Tue, 26 Jul 2011 15:56:07 +0100, Phil W Lee >>  wrote: > >> > > >>> Put in the simplest of terms, how much energy does it take to crack >>> a piece of expanded polystyrene foam? > > >> It matters not one little bit how much energy it takes to crack a >> piece of expanded polystyrene foam (the material which is also used >> in motorcycle helmets). > >> The purpose of the polystyrene is to absorb the energy from an >> impact; once that impact has taken place and the energy has been >> absorbed by the helmet - it can be totally destroyed. It has done >> its job. Someone has said that the standards authorities clearly >> agree that helmets may be totally destroyed in an accident. That >> does not mean that they have failed. The tests for motorcycle helmets >> (very similar to those tests for cycle helmets) are being used to >> test something like 90% of the accident scenarios which are seen in >> real life. Do you really think that the BSI, Snell, and the European >> Standards authority do not know how to test helmets effectively? Do >> you think that motorcycle helmet testing is pointless? > >>> The simple fact is that using current technology, it is not >>> possible to construct any helmet that is both wearable during >>> medium to high levels of exertion and provides any meaningful level >>> of protection against any but the most trivial impacts. The >>> impacts have to be both fairly low in magnitude (helmets are only >>> tested to an equivalent of falling over from a standstill onto a >>> hard surface) and directly radial. > >> In exactly the same way as motorcycle helmets are tested > > >>> Even the people who design and test helmets say they have never >>> actually seen one from a real world incident that performed in a >>> manner which would actually absorb any meaningful amount of >>> energy. > >> I assume that you have some cites for this outlandish claim > >>> It's all fairly simple physics and material science. > >> Indeed - just like your claim that the helmet has broken without >> using any energy whatsoever. > > Ah, so you either didn't read or didn't understand. > > Fine, let's try this again then: do you understand the difference > between brittle fracture and crushing? > > Also, do you consider Brian Walker to be suitably expert? The courts do. > 

So do you wear a helmet, Guy? Because if you do then you're obviously being deceitful and insincere somewhere along the way (two words which I'm sure no-one has ever associated with you before).