6. Conclusions

Therefore, it is anticipated that this hybrid control law can exert sufficient active damping to the CFRP panel, which is suitable for the noise insulation application. The schematic diagram of the hybrid control system is shown Figure 11. When the active insulation system starts to work, the acceleration signal

From the measured data, the proposed hybrid control scheme can realize wideband vibration reduction. For instance, at 83 Hz, the vibration reduction value is 13 dB; at 143 Hz, the vibration reduction value is 6.6 dB; at 194 Hz, the vibration reduction value is 5.3 dB; at 216 Hz, the vibration reduction value is 5.2 dB; at 273 Hz, the vibration reduction value is 4.3 dB; at 305 Hz, the vibration reduction

The SPL spectrums before control and after control are shown in Figure 13.

spectrums before control and after control are shown in Figure 12.

Noise and Vibration Control - From Theory to Practice

Measured acceleration signal (solid line: before control, dashed line: after control).

Measured sound pressure level (solid line: without control, dashed line: with control).

value is 5.9 dB.

Figure 12.

Figure 13.

92

In this chapter, the active damping approaches are adopted to improve structure's sound insulation performance in the low frequency range. The collocated sensor/actuator configuration is adopted to simplify the control law design. The NAF control law is proposed to suppress the plate's 1-1 mode, which radiates sound effectively and needs more control authority. The FVF control is proposed to suppress multiple vibration modes in wide range. In the experimental study, a CFRP panel is utilized as the control target and the NAF and FVF control laws are combined together to generate active damping to the CFRP structure. Experimental test results show the hybrid control law can realize wideband active damping and improve the plate's sound insulation performance significantly.
