We flew our SR20 this morning and after about 20 minutes we felt and heard what appeared to be a low rumbling and vibration coming from the rear of the aircraft. We had no power loss and the plane flew fine but this sound and vibration was very concerning to us. After about 5 minutes it stopped and reappeared about 10 minutes later. It lasted for about 5 minutes then disappeared again and we never heard or felt it again. After landing and looking at the aircraft we noticed that the wing-walk material on the step was peeled back and torn about 3/4 off the passenger side. Maybe this could have been the sound and vobration that we heard and felt. Anyone else had anything like this? The wing-walk material sucks being white and that fact that it’s peeling off with only 60 hours on the plane. Any thoughts?