Someone asked me to design a 6 feet diameter ball to be dropped for new year eve. It will be steel skeleton. What force should I keep in mind to resist?
Every time I watch "Rockin New Year's Eve with Dick Clark", the ball in Times Square drops real slow to add some suspense. I strongly suspect that's what they're doing, not pushing it off a ledge and having it free fall for 6 feet.
If that's the case, the dynamic loads should be negligible. If they're actually dropping the ball, the forces will be large, plus the ball might start rolling somewhere.
Calculate the velocity of the ball when it strikes the ground. For such a large diameter, you will need to consider drag forces.
Determine the coefficient of restitution between the ball and the object it is striking. This will be a function of the elastic properties of the two bodies. Determine the length of time the two objects are in contact before the ball bounces up. If the ball doesn't bounce up, determine how far its centroid moves after first making contact with the ground.
