Interior Acoustic Field Analysis of Hydraulic Excavator’s Cabin Based on Bem

2011 ◽  
Vol 141 ◽  
pp. 323-327 ◽  
Author(s):  
Yuan Wang ◽  
Jian Run Zhang ◽  
Xiao Bo Liu ◽  
Vanquynh Le
Keyword(s):  
Boundary Element ◽  
Acoustic Field ◽  
Sound Pressure ◽  
Sound Field ◽  
Element Model ◽  
Forced Response ◽  
Field Analysis ◽  
Acoustic Cavity ◽  
Acoustic Boundary Element ◽  
Force Excitation

Structure finite element model of excavator’s cabin is built, and the displacement response of cabin under the external force excitation is analyzed between 20Hz and 200Hz. In the analysis of acoustic characteristic of cabin, the boundary element model of the cabin internal acoustic cavity including the seat is created firstly. Where the result of forced response of the cabin’s structure is mapped to the boundary element model of the sound field inside the cavity as boundary condition, and the distribution of internal acoustic field is calculated and sound pressure response at the driver’s right ear is obtained. And then, acoustic boundary element grids is divided into different sections according to the corresponding structure section of the cabin to evaluate the contribution of sound pressure level at diver’s right ear from each part of cabin.

scholarly journals Simulation and Experimental Validation of Sound Field in a Rotating Tire Cavity Arising from Acoustic Cavity Resonance

2021 ◽  
Vol 11 (3) ◽  
pp. 1121
Author(s):  
Xiaojun Hu ◽  
Xiandong Liu ◽  
Yingchun Shan ◽  
Tian He
Keyword(s):  
Sound Pressure ◽  
Influence Factors ◽  
Sound Field ◽  
Element Model ◽  
Simulation Method ◽  
Cavity Resonance ◽  
Rotating Speed ◽  
Automobile Tire ◽  
Acoustic Cavity ◽  
Simplified Finite Element Model

As we all know, the tire acoustic cavity resonance noise (TACRN) can cause irritating noise in a vehicle, but it is evidently difficult to be weakened. To obtain accurately the characteristics of TACRN is a key step of attenuating TACRN. In this paper, a simulation method, in which a simplified finite element model of automobile tire with acoustic cavity introducing the rotation of automobile tire is established, is proposed to gain the sound field in the cavity of a rotating automobile tire. And the test of sound pressure in a rotating tire is also performed to validate the proposed simulation method. The comparisons between the simulation and experimental consequences show a satisfying conclusion. Furthermore, the influence factors of the rotating speed, the inflation pressure of the tire and the load on the sound field of automobile tire acoustic cavity are calculated and analyzed.

scholarly journals A System for Acoustic Field Measurement Employing Cartesian Robot

2016 ◽  
Vol 23 (3) ◽  
pp. 333-343 ◽  
Author(s):  
Maciej Szczodrak ◽  
Adam Kurowski ◽  
Józef Kotus ◽  
Andrzej Czyżewski ◽  
Bożena Kostek
Keyword(s):  
Acoustic Field ◽  
Energy Flow ◽  
Velocity Vector ◽  
Sound Pressure ◽  
Sound Field ◽  
Acoustic Energy ◽  
The Other ◽  
Object Shape ◽  
Movement Path ◽  
Optimum Path

AbstractA system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar) and particle velocity(vector) quantities. The aim of the system is to collect data with a high precision and repeatability. The system is employed for measurements of acoustic energy flow in the proximity of an artificial head in an anechoic chamber. In the measurement setup an algorithm for generation of the probe movement path is included. The algorithm finds the optimum path of the robot movement, taking into account a given 3D object shape present in the measurement space. The results are presented for two cases, first without any obstacle and the other - with an artificial head in the sound field.

Hull Disturbing Forces Due to Propeller Sources

2005 ◽  
Vol 36 (6) ◽  
pp. 12-20 ◽  
Author(s):  
R. Kinns ◽  
C.D. Pim
Keyword(s):  
Boundary Element ◽  
Low Frequency ◽  
Element Model ◽  
Frequency Effects ◽  
Twin Screw ◽  
Acoustic Boundary Element ◽  
Ship Vibration

An acoustic boundary element model of a modern twin-screw cruise liner is used to show how fluctuating pressures above the propeller, and hull forces that cause ship vibration, change relative to each other with the nature of propeller sources. The low frequency effects of fluctuating loads on the propeller in different directions are compared with the effects of unsteady cavitation. The implications of the results for specification of ship requirements and estimation of ship vibration are discussed.

A TECHNIQUE FOR PLANE-SYMMETRIC SOUND FIELD ANALYSIS IN THE FAST MULTIPOLE BOUNDARY ELEMENT METHOD

2005 ◽  
Vol 13 (01) ◽  
pp. 71-85 ◽  
Author(s):  
Y. YASUDA ◽  
T. SAKUMA
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Large Scale ◽  
Numerical Study ◽  
Sound Field ◽  
Field Analysis ◽  
Fast Multipole ◽  
Plane Symmetric ◽  
Sound Fields ◽  
Element Method

The fast multipole boundary element method (FMBEM) is an advanced BEM, with which both the operation count and the memory requirements are O(Na log b N) for large-scale problems, where N is the degree of freedom (DOF), a ≥ 1 and b ≥ 0. In this paper, an efficient technique for analyses of plane-symmetric sound fields in the acoustic FMBEM is proposed. Half-space sound fields where an infinite rigid plane exists are typical cases of these fields. When one plane of symmetry is assumed, the number of elements and cells required for the FMBEM with this technique are half of those for the FMBEM used in a naive manner. In consequence, this technique reduces both the computational complexity and the memory requirements for the FMBEM almost by half. The technique is validated with respect to accuracy and efficiency through numerical study.

scholarly journals TO THE CALCULATION OF ACOUSTIC FIELD CHARACTERISTICS FOR QUADCOPTER PROPELLERS

2019 ◽  
Vol 27 (4) ◽  
pp. 42-51
Author(s):  
Galina Ivanovna Sokol ◽  
Valeriy Yevgenovich Nekrasov ◽  
Vladislav Semenovich Zhmurko
Keyword(s):  
Mathematical Model ◽  
Unmanned Aerial Vehicles ◽  
Acoustic Field ◽  
Sound Pressure ◽  
Sound Field ◽  
Noise Distribution ◽  
Aerial Vehicles ◽  
Basic Law ◽  
Analytical Review ◽  
Scope Of Application

The work defines the area of use of unmanned aerial vehicles (UAVs) of the type of quadrocopter and calculated the acoustic field of propellers in order to reduce the level of noise at some distance. The main sources of noise, which are the hubs of the quadrocopter, are considered. The first samples of UAVs appeared in the middle of the last century as a separate type of promising weapons, but now quadrocopter,began to be actively used in the civilian sphere. The theory of the sound field of the aircraft's air propeller, which was proposed by L. Gutin to simulate the noise from each of the chochire screws of the quadrocopter, was carried out. A mathematical model has been created for calculating the total acoustic field all the of quadrocopter screws. The analysis and the defined area of use of UAVs of type quadrocopter  and the calculation of acoustic field of screws is given in order to reduce the noise level at some distance. The authors conducted an analytical review of the existing models of UAVs and quadrocopters, considered general examples of use of quadrocopters, their purpose and scope of application. On the basis of analytical review of constructions the fundamental scheme of quadrocopter for researches is given. The article is driven by the principal scheme of the chosen quadrocopter with the description of its main nodes. Based on the results of calculations, the noise distribution schedules of different frequencies in the space are constructed. The results from sound pressure levels for each of the five harmonics. Description of direction of acoustic fields on separate frequencies each of harmonics is constructed using the Besselyu function. Mathematical calculations have been performed in MathCad 2015. There are two forces on each screw element: thrust and resistance of the rotary motion. From the Basic Law of mechanics it follows that this element, in its turn, influences the environment with equal magnitude and opposable directed forces.

An Improved Formulation for Acoustic Eigenmode Extraction from Boundary Element Models

1990 ◽  
Vol 112 (3) ◽  
pp. 392-397 ◽  
Author(s):  
J. P. Coyette ◽  
K. R. Fyfe
Keyword(s):  
Eigenvalue Problem ◽  
Boundary Element ◽  
Element Model ◽  
Response Analysis ◽  
Alternative Procedure ◽  
Direct Response ◽  
Subspace Iteration ◽  
Analysis Technique ◽  
Acoustic Boundary Element ◽  
Iteration Technique

The acoustic boundary element method has been utilized primarily as a direct response analysis technique. Recently, methodologies have been published that enable the formulation of an eigenvalue problem from a boundary element model. These techniques, however, have been very slow due to the inefficient synthesis techniques used in solving the algebraic problems. In this paper, an alternative procedure is obtained which indirectly calculates the desired acoustic variables. This technique greatly enhances the calculation speed in setting up the eigenvalue problem and in determining the field pressures. A subspace iteration technique is outlined to solve the generalized unsymmetric eigenvalue problem. Examples are presented to show the accuracy of the method.

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