Err! Foam has a memory so once it has compressed it will return to its original size. You sir I would suggest may not know what you are talking about.
"Crushable foams are ideal for helmets designed for one hard impact. The cell walls crush on impact and slow the head gradually. A small portion of the energy is converted to heat as noted above. When foam crushes, it does not bounce back at the bottom like a spring to make the impact worse. But when you reach its crush limit, it will pass the rest of the impact energy straight through to your head."
EPS is a crushable foam.
"Not only did I not see bottomed out helmets, I didn’t see any helmet showing signs of crushing on the Inslde. This poses the question of whether the helmets are stiffer than infant heads or do infants just not hit that hard, The evidence is that most of the time infants don’t Mt all that hard."
Senior engineer at Bell Helmets in a letter to the CPSC.
i.e. the lack of visible evidence of crushing is evidence that the helmet was not hit that hard.
You were saying?
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