Experimental study of the evolution of composite baseball bat performance

As composite bats are used in the field, microdamage can be developed in the form of microcracks in the matrix, fibre breakage and ply delamination, thereby reducing the barrel stiffness and increasing the resulting batted-ball speed. To replicate this microdamage with field-use phenomenon in the lab, an accelerated break in (ABI) process is employed by rolling the bats in a press. In this research, a representative set of composite bats was subjected to repeated rolling and performance testing to explore the evolution of bat performance with ABI. This paper will explain the ABI process and discuss changes in bat performance and barrel stiffness as a result of rolling for a representative set of composite baseball bats.