Topology Optimization of Gearbox to Reduce Radiated Noise

2015 ◽  
Author(s):  
J. P. Wang ◽  
G. Liu ◽  
S. Chang ◽  
L. Y. Wu
Keyword(s):  
Topology Optimization ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Dynamic Loads ◽  
Field Point ◽  
Radiated Noise ◽  
Contribution Analysis ◽  
Acoustic Contribution ◽  
Mode Order

In this paper, topology optimization of gearbox to reduce the radiated noise is studied based on the analysis of modal acoustic contribution and panel acoustic contribution. Firstly, the bearing dynamic loads are obtained by solving the dynamic equations of gear system. Secondly, the vibration of gearbox is calculated using FEM and the radiated noise is simulated using BEM by taking these bearing dynamic loads as excitations. Thirdly, the panel having larger contribution to the sound pressure level (SPL) at a specific field point is found by panel acoustic contribution analysis (PACA), and this panel is taken as design domain. The mode order with larger contribution is determined by modal acoustic contribution analysis (MACA), and making corresponding natural frequency becomes far away from excited frequency is taken as a constraint. Finally, the topology optimization of gearbox is completed using SIMP method, and the ribs are arranged according to the optimization results. The results show that the equivalent sound pressure level at objective field point can be reduced obviously by using this method.

Optimal Rib Layout Design of Gearbox for the Reduction of Radiated Noise

2017 ◽  
Author(s):  
G. Liu ◽  
J. P. Wang ◽  
S. Chang
Keyword(s):  
Topology Optimization ◽  
Optimization Model ◽  
Sound Pressure ◽  
The Finite Element Method ◽  
Field Point ◽  
Radiated Noise ◽  
And Topology ◽  
Contribution Analysis ◽  
Acoustic Contribution ◽  
Element Method

In this paper, a method to determine the optimal rib layout of gearbox for the noise reduction is proposed based on acoustic contribution analysis and topology optimization. Firstly, the radiated noise is simulated using the finite element method (FEM) and boundary element method (BEM). The field point with maximum sound pressure is taken as the objective field point. Secondly, the surface of gearbox is divided into different regions and the region with maximum acoustic contribution to the sound pressure on the objective field point is found by acoustic transfer vector analysis and acoustic contribution analysis. Thirdly, the topology optimization model is established to reduce the velocities on the region with maximum acoustic contribution. Lastly, the topology optimization model is solved using the SIMP method and the ribs can be arranged according to the results of topology optimization. The simulation results show that the sound pressure on objective field point is reduced remarkably by using this method.

Investigation of Cavitation Phenomena on Noise of Underwater Propeller

2017 ◽  
Author(s):  
Amir Karimi Noughabi ◽  
Morteza Bayati ◽  
Mehran Tadjfar
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Control Strategies ◽  
Noise Analysis ◽  
Pressure Level ◽  
Broadband Noise ◽  
Marine Propeller ◽  
Cavitation Noise ◽  
Radiated Noise ◽  
Thrust And Torque

Underwater propeller cavitation noise is composed of tonal blade rate noise and high frequency broadband noise. Cavitation usually increases overall sound pressure level in the various frequency ranges which depends on the type of cavitation. This research had been carry out to predict the radiated noise from a marine propeller in presence of cavitation with various cavitation types. The analysis is performed by coupling an acoustic code based on the Ffowcs Williams-Hawkings (FWH) equation to unsteady Reynolds-averaged Navier-Stokes (URANS) which able to simulate multiphase flows in rotational domains. A brief summary of numerical method used to model the cavitation around the underwater propeller are presented and the thrust and torque coefficients are validated in different flow conditions by experimental results. The radiated noise along the shaft direction and perpendicular to the shaft direction is studied on both cavitating and non-cavitating propellers. Then, to predict the radiated noise due to cavitation in marine propeller, the computed sound pressure level (SPL) for non-cavitating marine propeller is compared with the SPL for the same propeller in cavitation conditions at various cavitation number and advanced coefficients. The noise analysis helps to determine the dominant noise source of the underwater propeller in different conditions, which will provide a basis for proper noise control strategies.

Vibration and Noise Damping Treatment for an Excavator Cab

2014 ◽  
Vol 889-890 ◽  
pp. 455-458
Author(s):  
Yong Zhen Mi ◽  
Yi Qi Zhou ◽  
Li Wang
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Material Layer ◽  
Contribution Analysis ◽  
Damping Material ◽  
Great Decline ◽  
Chlorobutyl Rubber ◽  
Acceleration Signals

Acceleration signals at the mounts of an excavator cab are collected and analyzed, on the basis of which causes of peak values in the sound pressure level (SPL) at the drivers right ear (DRE) are discussed. A damping material layer made up of chlorobutyl rubber is arranged to the cabs panels by simulations according to results of panel acoustical contribution analysis, which indicates a great decline of the SPL peak values.

scholarly journals Numerical and Experimental Investigation on Radiated Noise Characteristics of the Multistage Centrifugal Pump

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 793 ◽  
Author(s):  
Si ◽  
Wang ◽  
Yuan ◽  
Huang ◽  
Lin ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Source ◽  
Low Noise ◽  
Pressure Level ◽  
Radiated Noise ◽  
Noise Characteristics ◽  
Flow Induced Noise ◽  
Multistage Pump

The radiated noise of the centrifugal pump acts as a disturbance in many applications. The radiated noise is closely related to the hydraulic design. The hydraulic parameters in the multistage pump are complex and the flow interaction among different stages is very strong, which in turn causes vibration and noise problems because of the strong hydraulic excitation. Hence, the mechanism of radiated noise and its relationship with hydraulics must be studied clearly. In order to find the regular pattern of the radiated noise at different operational conditions, a hybrid numerical method was proposed to obtain the flow-induced noise source based on Lighthill acoustic analogy theory, which divided the computational process into two parts: computational fluid dynamics (CFD) and computational acoustics (CA). The unsteady flow field was solved by detached eddy simulation using the commercial CFD code. The detailed flow information near the surface of the vane diffusers and the calculated flow-induced noise source was extracted as the hydraulic exciting force, both of which were used as acoustic sources for radiated noise simulation. The acoustic simulation employed the finite element method code to get the sound pressure level (SPL), frequency response, directivity, et al. results. The experiment was performed inside a semi-anechoic room with a closed type pump test rig. The pump performance and acoustic parameters of the multistage pump at different flow rates were gathered to verify the numerical methods. The computational and experimental results both reveal that the radiated noise exhibits a typical dipole characteristic behavior and its directivity varies with the flowrate. In addition, the sound pressure level (SPL) of the radiated noise fluctuates with the increment of the flow rate and the lowest SPL is generated at 0.8Qd, which corresponds to the maximum efficiency working conditions. Furthermore, the experiment detects that the sound pressure level of the radiated noise in the multistage pump rises linearly with the increase of the rotational speed. Finally, an example of a low noise pump design is processed based on the obtained noise characteristics.

CAE Technology Applied to Range Hood’s Noise Control and Optimization Design

2011 ◽  
Vol 338 ◽  
pp. 543-546
Author(s):  
Hu Yu ◽  
Hong Hou ◽  
Liang Sun
Keyword(s):  
Sound Pressure Level ◽  
Optimization Design ◽  
Sound Pressure ◽  
Element Model ◽  
Pressure Level ◽  
Sound Power ◽  
Radiated Noise ◽  
Radiated Sound ◽  
Cae Technology ◽  
Radiated Sound Power

In this study we use the CAE technology to compute and reduce the radiated noise of range hood. First, a finite element model of a typical range hood is created using Hypermesh. Then, the surface particle velocity is carried out in Nastran, and the radiated noise is calculated by Sysnoise. Finally, the DOE-based structural optimization is preformed using iSIGHT-FD, in which the sound pressure level at four sensitive points and the radiated sound power are selected as the objective function and the thickness of four panels are adopted as design variable. In addition, the weight of the range hood as a constraint is kept no more than its original weight. As a result, a maximum radiated sound power reduction of 3.66W and a maximum sound pressure level reduction of 4.7 dB are successfully achieved. It shows the CAE technology is a very efficient and effective method for reducing radiated noise.

Investigation and Optimization of a Spare Wheel Well to Reduce Vehicle Interior Noise

2003 ◽  
Vol 11 (03) ◽  
pp. 425-449 ◽  
Author(s):  
Steffen Marburg ◽  
Hans-Jürgen Hardtke
Keyword(s):  
Transfer Function ◽  
Sound Pressure Level ◽  
Structural Component ◽  
Sound Pressure ◽  
Pressure Level ◽  
Frequency Range ◽  
Noise Emission ◽  
Noise Transfer Function ◽  
Contribution Analysis ◽  
Design Variables

Optimization of structures with the intention to reduce noise emission has become an efficient tool during the past decade. Various approaches and applications have been published and will be briefly reviewed in this paper. Then, the structural component model of a spare wheel well and the fluid model of a sedan cabin are described. The noise transfer function is defined as the sound pressure level in vicinity of the driver's ear due to a harmonic force excitation at engine supports. The frequency range of 0–100 Hz is considered. In a first investigation, it is tested whether stiffening of the entire structural component really decreases the noise transfer function. It can be seen that this stiffening mainly affects noise emission in the upper frequency range. In a contribution analysis, i.e. analysis of the surface contribution to the noise at the driver's ear, the original model and the stiffened model are compared. This contribution analysis includes frequency ranges by summation of contribution and/or contribution levels. Modification of the structure by design variables consists of modification of the shell geometry, i.e. curvature. Two regions are selected at the bottom of the wheel well. Optimization of 30 design variables leads to a gain of 1.15 dB in the objective function being the root mean square value of the sound pressure level at the driver's ear. Finally, we discuss the results. In most papers on structural acoustic optimization, higher decreases have been reported. An explanation is provided, why this was not possible for the structure that has been investigated here. The new shape, however, seems to be a reasonable choice.

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