Heres Y carl,

It's not that they get WARPED, they're just flimsy, floppy arrays. The Silicon cells are on/in a thin polymer(?) film and held taut by a flexable frame. Good for rolling and unrolling. BAD for everything else.

Materials expand and contract depending on their temperature. When these go from "night" to "day" they experience a mechanical shock because they're so thin and expand/contract so quickly. This shakes the whole damn spacecraft every 45 minutes. Thats why both pairs have been in rough shape when you see them being removed.

The new ones have a thick frame that gets rid of most of the vibration problems. There also more efficent solar cells (GaAs I think) which give more bang for the buck.

I dunno about ISS. I would HOPE that they are more rigid than Hubble's were.....