本研究目的是探討鈦金網球拍之固有振動特性。透過振動模態實驗的分析方法,蒐集球拍受激振後,所呈現的自然頻率及阻尼比,並分析鈦金網球拍之振型,藉此瞭解鈦金球拍本身之固有振動特性。研究使用Head Ti S2之中型拍面之鈦金網球拍進行衝擊實驗,應用衝擊鎚對拍柄固定處施以脈衝激振,並以加速規爲感應器,擷取空拍框上三十一個座標點的激振資料,將所得資料透過電荷放大器、頻譜分析儀與STAR模態分析軟體之處理與運算,求出各模態之振型、自然頻率與阻尼比參數,並經過純量三重積之模態判定矩陣來應證模態之準確性。 完成實驗之過程,獲得如下結論: 一、鈦金網球拍的振動模態之自然頻率參數,分別爲第一自然頻率32.560赫茲,第二自然頻率86.724赫茲,第三自然頻率192.665赫茲,第四自然頻率459.237赫茲,第五自然頻率541.018赫茲,並未呈現有較高之自然頻率。 二、鈦金網球拍的振動模態之阻尼比參數,分別爲第一模態阻尼比0.9764,第二模態阻尼比1.8659,第三模態阻尼比1.6621,第四模態阻尼比0.5413,第五模態阻尼比0.7012,顯現鈦金網球拍有較高阻尼比的優勢。 三、鈦金網球拍之振動模態振型,分別爲第一模態呈現低頻之擺動模態;第二模態 呈現低頻之扭曲模態;第三模態呈現中頻單次彎矩模態;第四模態呈現高頻之複合模態;第五模態呈現高頻之二次彎矩模態。
To assess the characteristics of the vibration on Titanium alloys tennis racket by the natural frequency and the damping ratio using the impact experiment method. The Titanium alloy tennis racket (Head Ti S2) was applied in the impact experiment. The racket was stimulated by the impulse hammer at the fixation, and the vibration of thirty-one chosen points on the frame was gathered by the accelerometers. These data were analyzed by the Change amplifier, Dynamics Spectrum Analyzer, and Star Structural Measurement System. The first five natural frequency are 32.560Hz, 86.724Hz, 192.665Hz, 459.237Hz, and 541.018Hz respectively, and the damping ratios are 0.97640, 1.86589, 1.66213, 0.54134, and 0.70124 in order. Moreover, the first five vibration modes are low-frequency diving board mode, low-frequency twisting mode, intermediate single bending mode, high-frequency compound mode, and high-frequency two-order bending mode. Since there is no significantly higher natural frequency, moreover, consisting higher damping ratio than others. We conclude that the Titanium alloys is a suitable material to manufacture the tennis racket.