The Hong Kong University of Science and Technology

Hong Kong Baptist University

Zhen Dong

Ping Sheng

Xiaonan Zhang

Ho Yiu Mak

Guancong Ma

Jie Pan

Rotational translation of an inertial mass rotor is used for providing damping of low frequency noise and vibration. An axial component is mounted so as to translate axial movement of an inertial linearly-displaceable member to rotational movement of an inertial mass rotor. The translation to rotational movement of the inertial mass rotor provides inertial amplification in the form of translational-rotational coupling. This enables the construction of a compact assembly, which allows light ultra-low frequency resonances to be concentrated, and which absorbs such low frequency noise energy.

Compact low-frequency wave absorption device

A soft boundary structure is implemented using a resonator structure capable of receiving sound or vibration, establishing resonance coupled with received sound or vibration, and creating a reflection with a pi phase factor. A soft boundary is located on or closely adjacent the resonator structure. The soft boundary cooperates with the resonator structure to attenuate the sound or vibration.

Soft acoustic boundary plate

An active sound barrier has at least one passive sound absorber at or near a boundary location. A microphone provides an output to a frequency division module, in which a plural of frequencies are filtered to provide outputs corresponding to frequency segments of the receiving transducer output at respective ones of the frequencies. An active driving circuit drives plural speakers or output transducers at respective ones of the frequencies, with at least a subset of the speakers or output transducers at or close to the barrier. The speakers or output transducers cooperate with the passive sound absorber to reduce noise across a wide frequency band as well as to effect an electrically switchable soft boundary.

Growing community of inventors

Hong Kong, China

Zhen Dong