Figure 3

Experimentally determined natural frequency and damping ratio. (A) Bending vibration test for measuring the step response associated with the bending mode. (B) The vibration data were bandpass filtered at 0.1–10.0 Hz to remove noise. Subsequently, the response was fit by the analytical solution of the damped free vibration problem. (C, D) The natural frequency and the damping ratio obtained from the fitting of the observation. (E) The relationship between natural frequency and Young’s modulus. Values in C and D are means ± s.e. (standard error; n = 4). Tukey’s HSD test was used to examine the statistical significances at p < 0.05 and different alphabets indicate significant differences. † and * indicate statistical significance in correlation coefficient at p < 0.1 and p < 0.05, respectively.