turbulence
When flying on the big jets I'm always a passenger and spend a lot of my time looking out of the window. Not being the best passenger in the world I am always concerned by the way wing tips flex and engines rattle around in their mountings during take off and turbulence.
I'm well aware they are designed to do this but how much stress can they take? Do large planes ever fall apart due to excessive vibration?
I would appreciate any views from people with a bit of a technical background.