Performance assessment of wood, metal and composite baseball bats

The purpose of this investigation was to develop and verify a predictive capability of determining baseball bat performance. The technique employs a dynamic finite element code with time dependent baseball properties. The viscoelastic model accommodates energy loss associated with the baseball's speed dependent coefficient of restitution (COR). An experimental test machine was constructed to simulate the ball–bat impact conditions in a controlled environment and determine the dynamic properties of the baseball. The model has found good agreement with the experimental data for a number of impact locations, impact speeds, bat models and ball types. The increased hitting speed generally associated with aluminum bats is apparent, but not for impacts inside of the sweet spot. A reinforcing strategy is proposed to improve the durability of wood bats and is shown to have a minimal effect on its hitting performance. The utility of using a constant bat swing speed to compare response of different bat types is also discussed.