短語詞組短語free vibration natural frequency 自由振動固有頻率vibration amplitude and natural frequency 振幅及自振頻率natural vibration frequency analysis 自振頻率分析natural vibration frequency 固有振動頻率;自振頻率natural -vibration frequency 固有振動頻率natural frequency vibration test 固有頻率振動試驗second -order natural vibration frequency 二階自振頻率 返回 vibration natural frequency