REBOUNDING OF GALILEAN CANNON FROM A RIGID WALL1)

The Galilean Cannon involves a chain of different size balls rebounding on a rigid wall. Three mechanical models are used to analyze the rebound process: (1) The rebounding is treated as a series of separated one-to-one "elastic" impacts; (2) The rebounding is treated as a one-dimensional multi-body impact, using the Hertzian contact model to describe the rigid body interactions; and (3) The rebounding process is simulated using a 3-D FEM software. Each model reveals a disintegration phenomenon of the ball-chain after impact. It is shown that the rebound speed of the smallest ball in the far end of the chain can be several times larger than the incident speed. The increase of the rebounded speed is more significant when a spacing is assigned between the balls so that the multi-impacts occur as "separated" impact events. Also the differences among the three analytical models are discussed. Experiments are conducted with agreeable results as compared with the theoretical analysis.