But what happens inside the skin?
WizofOz
I am not a composite structures person. But I had an interesting conversation with someone who said he was one, at ORD the other day.
He confirmed what you say - you hit the skin with a 5 pound mallet and you'll break the mallet before you break the skin.
But he also said that while there was no apparent damage inside or outside, when you got to layer 4 or 5 (eg if there are 9 layers) you sometimes see microscopic mechanical changes from some kind of internal refraction which are not seen on the outer layers. Which takes us back to 'how would you know if the aircraft had been damaged if johnny honeycart or ecoli caterers smack the skin and don't report?' Was he talking out of his afterburner?