網球拍拍柄材質之振動阻尼比研究
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Date
1998-07-01
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Publisher
中華民國體育學會
Abstract
本研究的主要目的在探討不同網球拍拍柄結構之振動特性。實驗中使用五 種不同材質的網球拍，分別為100%碳纖維、100%玻璃纖維及碳纖維和玻璃 纖維比為7:3、5:5.3:7之網球拍為主要測試的對象，五支網球拍 的重量、網壓、勁度、平衡點和拍喉位置前的條件都在相同控制下，進行網球 撞擊的振動測試和控球能力測試。振動測試主要是以BioPAC的訊號處理系統 和一個Kistler(20g)、一個BioPAC(50g)的加速規進行數據的採集，採樣 頻率為2000Hz網球的撞擊速度均固定為4.09m/s。 實驗結果發現100%碳纖維網球拍在中心撞擊與偏心撞擊時，其振動之第 一模態皆有較高的阻尼比(p<.05)。阻尼比隨著網球拍握柄的玻璃纖維含量的 增多而有明顯降低的情形。所以，當相同之撞擊力傳遞經過100%碳纖維球拍 時，會因其阻尼比較大的緣故，而對傳遞來的振動力有較佳的阻振效果，並減 少了振動的趨穩時間，因此，給予握拍手有較少的負荷。
The purpose of the study was to analyze the vibration of differential tennis racket grip materials. Five different kinds of tennis racket grip, their materials were composed by mixing carbon fiber and glass fiber in the ratio of 10 to 0,7 to 3,5 to 5,3 to 7, and 0 to 10, were used in this study. All of them had the same weight, string tension, stiffness and balance. The experiments of the study were to test their vibration and to find damping ratio. Two accelerometers (2000 Hz) and BioPAC system were used to acquire the vibrational signals. The impact of tennis ball was set in the velocity of 4.09 m/s. The selected variables in the experimants were tested by one-way ANOVA at=.05 significant level. The results of this study indicated that the pure carbon racket made racket had a higher damping ratio on the center and off-center impact. The damping ratio was significant decreased as the content of glass fiber in the racket was getting increased. Therefore, base on the vibrational analysis among the differential material composition of tennis rackets, it concluded that by increasing the content of glass fiber in the racket, it would be increasing the load in the tennis player's arm. Then, indirectly this phenomenon might affect the athlete's performance.
The purpose of the study was to analyze the vibration of differential tennis racket grip materials. Five different kinds of tennis racket grip, their materials were composed by mixing carbon fiber and glass fiber in the ratio of 10 to 0,7 to 3,5 to 5,3 to 7, and 0 to 10, were used in this study. All of them had the same weight, string tension, stiffness and balance. The experiments of the study were to test their vibration and to find damping ratio. Two accelerometers (2000 Hz) and BioPAC system were used to acquire the vibrational signals. The impact of tennis ball was set in the velocity of 4.09 m/s. The selected variables in the experimants were tested by one-way ANOVA at=.05 significant level. The results of this study indicated that the pure carbon racket made racket had a higher damping ratio on the center and off-center impact. The damping ratio was significant decreased as the content of glass fiber in the racket was getting increased. Therefore, base on the vibrational analysis among the differential material composition of tennis rackets, it concluded that by increasing the content of glass fiber in the racket, it would be increasing the load in the tennis player's arm. Then, indirectly this phenomenon might affect the athlete's performance.