不同材質的桌球拍底板對於撞擊特性的影響

桌球拍底板中的複合材質和結構種類繁多，很多選手或是業餘玩家在底板上的選購，大多是聽取他人的經驗談作為評估，但是這些都欠缺科學根據，也無法量化，所以本研究目的在探討不同材質的桌球拍底板對於擊球特性的影響。實驗中使用純木、玻璃纖維和碳纖維等不同力材材質的底板。透過高速攝影機擷取底板撞擊時的影片，利用影片分析軟體，來比較不同底板的自然頻率、持球時間和反彈恢復係數。實驗結果顯示不同材質會在第一振動模態中有不同的自然頻率，碳纖維最高，玻璃纖維和純木較低。自然頻率較高，振幅較小，屬於勁度較大的底板，可減少球拍與球之間因碰撞造成的能量損失，因此持球時間較短，恢復係數也較高；自然頻率較低的底板則相反。同時發現自然頻率與持球時間以及恢復係數分別呈現負相關及正相關；不同撞擊速度與持球時間呈現負相關，與恢復係數呈現正相關。未來，可以利用自然頻率與持球時間、恢復係數的關係，幫助打球者依據自己的需求去選擇一個合適的底板。

關鍵字

振動模態；持球時間；恢復係數

並列摘要

The construction and compound materials of the blades vary greatly; amateur as well as professional players often select their blades based on the information given by friends and colleagues. However, the information often lacks scientific basis, and thus could not be quantified. This study investigated the impact properties of table tennis blades made by three types of materials: wood, glass fibers and carbons. The nature frequencies of the blades were acquired by the accelerometer while ping-pong balls were projected by the serving machine. This information was then compared to both the holding time and the COR (coefficient of restitution). The results showed that different materials had different natural frequencies; the carbon blade is the highest, and the glass fiber and the wood blades were lower. The higher the natural frequency was, the smaller the amplitude was as expected. Energy loss was reduced when the balls hit the blades. Therefore the holding time was shorter but the COR was higher. Then the lower nature frequency blades had the opposite results. The results also showed a positive correlation between the natural frequencies and COR, but a negative correlation between the natural frequency and the holding time. We also found that a positive correlation between impact velocity and COR and a negative correlation between the impact velocity and the holding time. In conclusion, a chart could be developed according to the results that provided information for players to choose the blades based on their skill levels and competition strategies.