Abstract
A pitching machine of roller type for baseball is easily achieved a variable balls. An official hard-baseball, having a seam, is observed to affect variations in the ball's spin and the projected angle. In this study, a moving behavior and a contact stress state of the pitched ball with the roller type pitching machine is analyzed using a commercial dynamic finite element code (ANSYS/LS-DYNA). The linear velocity and the spin revolution of the pitched ball are monitored using a high-speed video camera, and those pictures compared with the finite element analysis. It is considered that the seam of the ball negatively influences the throw accuracy of the pitching machine.
