Do all wood bats perform the same?

Engineering of Sport 15 - Proceedings from the 15th International Conference on the Engineering of Sport (ISEA 2024)

The wood bat is a necessary tool used by batters in professional baseball. The question arises as to whether nominally identical wood bats perform the same, where “nominally identical” means the bats have the same length, weight, weight distribution, and shape. In this context, performance is defined as batted-ball speed under some standard game conditions. Given the constraints, such bats will likely be swung identically, so that the only feature that distinguishes their performance is the bat-ball coefficient of restitution (BBCOR), a measure of energy dissipation in the bat-ball collision. A larger/smaller BBCOR means less/more energy dissipation and consequently a greater/lesser batted-ball speed. While the energy dissipated in the bat-ball collision is primarily in the baseball, the bat also matters in that the collision can transfer energy to the bat in the form of bending vibrations. The latter is especially the case for impacts removed from the so-called sweet spot, which minimizes vibrations and maximizes performance. The objective of the present study is to determine whether there are differences in performance of nominally identical bats and to see how such difference might correlate with differences in the vibrational properties of the bats. The study focuses not only on differences at the sweet spot, but also on differences at other impact locations.