野球の『流し打ち』における飛距離を最大にする最適なインパクト

抄録

The purpose of this study was to extract optimal bat orientation angle and ball-impact position for maximizing flight distance in opposite-field hitting. Three-dimensional finite element analysis method was used to construct an impact model between a baseball and a wooden baseball bat, and a series of simulations with various impact conditions were conducted. Horizontal bat angle was set in a range from -31 to 20° and vertical bat angle was set from 0 to 51° with an interval of 3°. The line of impact was set to incline in a range from 5 to 40° with an interval of 5°. The linear and angular velocities of the batted ball, the angle from horizontal and from center line of the batted ball immediately after impact were determined for each simulated condition. Additionally, flight distance and ball drop point were calculated. The results showed that near maximum flight distance (> 90m) toward the opposite field for the given velocities of ball and bat was obtained by an impact with a large range of horizontal bat angle (-22~-7°) and the line of impact inclined at 20° when the vertical bat angle was zero (the bat head is in the same height as the grip-end). When the vertical bat angle was as large as 45° (the bat head is located lower than the grip-end), slightly reduced maximum flight distance (80-88m) was obtained with a narrow range of horizontal bat angle (2~14°) and the line of impact inclined at 20~25°.