516 Analysis of 3-Dimensional Sound Field by the Boundary Element Method

A two-dimensional boundary element method with a constant element type was adopted to study the sound field of a building near a roadway. First, a factor analysis of the computed results has been done, which include the element length, the Hankel functions’ calculation accuracy, and numerical integration accuracy. Then, boundary element method is applied to calculate building attenuation with different building aspect ratios and different frequencies with balconies, followed by drawing of the sound field distribution diagram. The calculation results revealed the following: (1) a wider building results in a more severe sound attenuation; (2) balconies on different floors produce a reduction of approximately 15 dB for broadband spectral characteristics of A-weight road traffic noise, and the maximum values appear at the bottoms of balconies; (3) for the points in the balconies, higher sound frequencies are correlated to larger insertion loss, with the insertion loss increasing from 3 dB to >10 dB when the sound frequency increases from 20 to 4000 Hz; (4) calculations of three typical frequencies indicate that the insertion loss of 500 Hz (main frequency of heavy vehicles) is 6 dB less than that of 800 Hz (main frequency of light vehicles), i.e. the flow control of heavy vehicles could conspicuously improve the ambient acoustic environment of buildings near a roadway.

Download Full-text

Numerical Analysis of 3-Dimensional Contact Problems with Friction by Special Boundary Element Method.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A ◽

10.1299/kikaia.57.3010 ◽

1991 ◽

Vol 57 (544) ◽

pp. 3010-3015 ◽

Cited By ~ 5

Author(s):

Kunihiko KAKOI

Keyword(s):

Numerical Analysis ◽

Boundary Element Method ◽

Boundary Element ◽

Contact Problems ◽

Special Boundary ◽

3 Dimensional ◽

Element Method

Download Full-text

Reconstruction of transient pressure and acceleration over a tire surface using the inverse time domain boundary element method

MATEC Web of Conferences ◽

10.1051/matecconf/201928304014 ◽

2019 ◽

Vol 283 ◽

pp. 04014

Author(s):

Yang Zhang ◽

Chuanxing Bi ◽

Xiaozheng Zhang ◽

Yongbin Zhang ◽

Liang Xu

Keyword(s):

Boundary Element Method ◽

Boundary Element ◽

Time Domain ◽

Domain Boundary ◽

Sound Field ◽

Rigid Sphere ◽

Transient Pressure ◽

Retarded Time ◽

Reconstructed Surface ◽

Element Method

The inverse time domain boundary element method (ITBEM) that is derived from the direct time domain boundary element method by eliminating the retarded time is able to reconstruct the transient pressure and flux on the surface of an arbitrarily shaped source by measuring the pressure on a hologram surface. In the present work, the ITBEM is applied to reconstruct the transient pressure and acceleration over the surface of a tire which is supported away from the ground in a semi-anechoic chamber. The tire is impacted by a rigid sphere to generate a transient sound field, and the measurement is controlled by a trigger which is connected to an acceleration sensor stuck on the surface of the tire. The pressure and acceleration on the surface of the tire are reconstructed from the holographic pressure measured by array microphones. By visualizing the pressure and acceleration with respect to the elapsed time, the wave propagation phenomenon of the pressure and acceleration on the surface of the tire is shown clearly. The comparison of the reconstructed surface acceleration to the measured one demonstrates the effectiveness of ITBEM for transient sound field reconstruction.

Download Full-text