An Investigation of Wood Baseball Bat Durability as a Function of Bat Profile and Slope of Grain Using Finite Element Modeling and Statistical Analysis

Abstract

To counter a perceived increase in multi-piece fracturing of wood baseball bats, Major League Baseball implemented standards to regulate the quality of wood used in the making of professional-grade baseball bats. These specifications included a minimum density as a function of wood species and a standard related to slope of grain (SoG). Following the implementation of these specifications in 2008, there was a 65% reduction in the multi-piece failure rate. It is hypothesized that a further reduction in the breakage rate can be realized through the implementation of regulations on allowable bat profiles. In the current work, a parametric study was conducted to develop a quantitative understanding of the relationship between bat durability (i.e., resistance to breaking), SoG, and bat profile, thereby obtaining data to support or refute the hypothesis. Finite element models of the bat/ball impact of four different popular bat profiles were created using LS-DYNA software. Similarities and differences between bat profiles impacted at two relatively vulnerable axial locations are presented and discussed. Lastly, the respective bat durabilities for all of the profiles were compared using a probability analysis that considers the SoG, impact location, impact velocity, and it predicts an in-service bat durability.