Measurement of Natural Frequency and Damping Free Vibration test(logarithmic decrement method) Forced vibration test: ambient vibration(vibration due to environmental excitation) Forced vibration Forced vibration:resonance test Nature frequency Damping ratio 180 g=0.01 0.1 002 90 5=1 Frequency ratio/n —0.1-02…0.5 目 二水二程季院 Measurement of Natural Frequency and Damping • Free Vibration test (logarithmic decrement method) • Forced vibration test: ambient vibration (vibration due to environmental excitation) Forced vibration  Forced vibration: resonance test • Nature frequency • Damping ratio