新型網球對球拍碰撞之動力學分析

The Dynamic Analysis of Tennis Racket due to New Stylus Tennis Impacts

丁麗芬(Li-Fen Ting) ； 周中明(Chung-Min Chou)

《北體學報》 9期 (2001/12) Pp. 219-234

https://doi.org/10.6167/TPEC/2001.9.19

摘要

本研究是探討新型網球對球拍碰撞之動力學分析，研究分為兩大部分：第一部份是瞭解新型網球與標準網球碰撞球拍之彈性恢復係數的差異。第二部份是瞭解新型網球與標準網球碰撞球拍之振動響應的差異。本研究是應用碰撞實驗法，採用一隻Wilson Hammer3.0大拍面之網球拍作為實驗工具，第一部份將拍柄及拍頭鉗鋏固定於平檯，以數位錄影機，蒐集兩種不同的網球自一公尺的高度以自由落體之方式落於拍面後之反彈高度，進行新型網球對球拍碰撞之彈性恢復係數之研究。後項振動響應實驗，是應用同一支球拍，將拍柄鉗鋏固定於測力板上，將測力板之接線連接於電荷放大器及Kistler類比數位轉換卡，依相同方式蒐集資料，進行新型網球對球拍碰撞之振動響應之研究。本研究獲如下之結果（一）新型網球在碰撞球拍後，產生之反彈恢復係數不如目前所使用之標準網球。（二）在振動響應方面，新型網球卻有著較正面之效應，其碰撞球拍後所造成的衝量較標準網球為低。

關鍵字

新型網球 ； 恢復係數 ； 振動響應

並列摘要

The purpose of this study is to make a dynamic analysis of tennis racket due to new stylus tennis impacts. The study is divided into two parts to take the newly stylus tennis ball and traditional tennis ball, two different sized balls as the research subjects. METHODS: Prior to testing, the Wilson Hammer3.0 tennis racket was strung with Prince synthetic gut 16L at tension of 58pound. The racket was gripped on a high speed camera and a KISTLER force plate. The two different tennis balls positioned at a height of 1 meter was dropped to the racket. The balls impacted vertically on the geometric center of the racket. The area was impacted for 20 trials. The sampling rate and data collection time of the force plate was set at 1024 Hz and 4 seconds, respectively. ANALYSIS METHODS: The raw data were measured by Bioware software and vibration forces were analyzed by Fast Fourier Transform into the frequency domain. RESULT: The result of this experiment can be concluded as follows: 1. After the ball/racket impact, the COR (Coefficient of Restitution) made by the new stylus tennis ball is less than the traditional tennis ball. 2. After the ball/racket impact, the vibration response of the newly stylus tennis ball is lower than that of the traditional tennis ball.