Portable Low-Frequency Noise Reduction Device for Both Small Open and Closed Spaces

Abstract

Noise pollution has been given more attention due to its negative impacts on human health and disease. The portable low-frequency noise reduction device we developed in this research can provide an effective way for solving low-frequency noise pollution problem in the small space. This work describes the design principle and the prototype structures for two versions of V1.5 and V2.0 and builds the noise test systems for small spaces, respectively. These devices, installed on the outer surface of the small spaces, can automatically identify the noise spectrum and implement noise reduction by means of the active noise control (ANC) technology. The testing results indicate that the noise can be reduced 12 dB in the range of 250 Hz~400 Hz for the small closed space while, for the small open space, the best effect of 5.88 dB occurs in the optimal frequency of 450 Hz. These effects will be weakened with the increasing distance away from the source and show the obvious axisymmetric distribution in the inverted cone space.

Study of the nonlocal active sound control with preservation of desired field in time domain

“…This makes the original field from the primary sources unattainable. In some practical applications, mostly related to the noise control in ventilation, this problem is partially resolved via directional measurements (see, e.g., (Huang et al, 2011;Jakob and Moser, 2003a,b;Kwon and Park, 2011;Sieck and Lau, 2011;Wang et al, 2016)). In (Ryaben'kii, 2011), it is proposed to solve an auxiliary local initial-boundary value problem across the control boundary to generate the control function.…”

An Efficient Reanalysis Method for Topological Optimization of Vibrating Continuum Structures for Simple and Multiple Eigenfrequencies

“…K and M are × the stiffness matrix and mass matrix, respectively. The ℎ eigenfrequency and the corresponding eigenvector can be obtained by solving (3). represents the number of the candidate eigenpairs, and it is suggested to be larger than that prevents the ℎ eigenfrequency exchange its order with the neighbouring eigenfrequency during the optimization process [2].…”

“…In classical topological optimization, the main purpose is concerned with the material distribution that represents the optimal layout in the admissible design domain [1]. The frequency optimization for vibrating structures is avoidance of resonance for the structure subjected to external excitation frequencies within a given interval [2][3][4]. For the optimal design procedure, two main subjects are needed to be treated carefully.…”

An Optimization Method for Maximizing the Low Frequency Sound Insulation of Plate Structures

“…There are numerous types of noise around buildings that seriously influence people's living quality [1]. Among these noises, low frequency noise is a major component of many occupational and community noises which is emitted by numerous sources in the society [2][3][4]. The lack of attenuation of low frequency noise by walls, windows, and other structures and its pervasive ambient levels make low frequency noise a factor of critical importance to people's living quality and health.…”