Adaptive active methods and means for reducing noise
and vibration of mechanisms and equipment

Purpose

Development of new active adaptive means for reducing wide-band noise and vibration of mechanisms, equipment, and plants installed on ships and vehicles, as well as in various rooms.

Degree of readiness Prototype of the system of broadband low-frequency noise suppression

Adaptive active methods for reducing noise and vibration are developed and justified. Algorithms and a software are developed, and a computer simulation of the technical solutions proposed for active suppression of noise and vibration is performed. The structure and the adaptive algorithms of controlling a one-dimensional and a multidimensional active systems of broadband noise suppression are developed. A prototype of the system of low-frequency noise suppression in an air duct of a ship fan is manufactured and tested. In the frequency range from 50 Hz to 250 Hz, the effect of sound suppression was 20-22 dB.

Technical approaches are developed for designing active systems of noise and vibration suppression in the frequency range 1-5 kHz on the basis of the expansion of the characteristics of the noise and vibration fields in orthogonal spatial harmonics. A prototype of the system with 36 combined receivers and transmitters (dipoles and monopoles) is manufactured. The system is tested, and the noise suppression by 10-25 dB in the frequency range 1.5-4.5 kHz is obtained.

The possibilities of the practical application of active noise suppression means are considered and estimated as applied to turbine and compressor noise and to noise transmitted through the windows into rooms.
Noise spectrograms
Noise spectrograms:
(1) the active system is turned off;
(2) the active system is turned on.

The results of work already performed at the Acoustics Institute are sufficient to fulfil an order for the R&D aimed at the development of active systems of noise and vibration suppression.