テニスラケットの動力学とコンピュータ援用設計 : モード特性におよぼす諸因子の影響と設計への指針

抄録

As a step toward the goal, i. e., the establishment of racket dynamics and the proposal of an improved evaluation system for optimum design, the effects of the support conditions of grip and the gut strings on the dynamic characteristics of the two different type of rackets are investigated using experimental modal analysis. The results show that the damping ratio and the decay rate of each mode are much greater and the damping of each mode scatteres wider under the grip constraint condition than those of free-support, and also show that the gut strings contribute very little to the modal parameters within the freguency ranges of 600 Hz, in which no membrain modes appear, but the damping is very small relative to the time during the ball/racket impact and the acceleration is large even in high-frequency modes. Accordingly, it may be safely assumed that the higher modes and the magnitude of acceleration are responsible for the stability of hitting surface.