Originally Posted by
caterham
you sure speak with a lot of authority for someone that has such a simplistic understanding of how & why a helmet dissipates energy.
the semi-resiliant foams used in helmets are by their nature brittle and are prone to cracking & destructive shear deformation during the impact as they conform to the wearer. they would not do their job otherwise-ie dissipating & spreading energy over time/distance/surface area by compression, deformation & shear. the whole process is a destructive one, right down to the cell structure of the foams themselves. so long as the foams remain positioned and located between the wearer and the point of contact , they are capable of and are indeed performing their function.
Excuse me? How dare you presume to evaluate my understanding based on a simplistic explanation given for the sake of your little pea brain.
A cracking helmet isn't conforming to anything. It's moving out of position, no longer between the wearer and the point of contact, where it is no longer capable of performing its function. Besides, regardless of how it works it sure as hell isn't preventing any skull cracking or absorbing more than a small percentage of an impact at speed and to the best of my knowledge, no designer, no physician, no regulating authority, or anyone else except for some ignorant safety nannies has ever claimed otherwise.
Mods, this thread is cooked, move it over to A&S where it belongs.