scholarly journals Prediction of Squeal Noise Based on Multiresolution Signal Decomposition and Wavelet Representation—Application to FEM Brake Systems Subjected to Friction-Induced Vibration

2020 ◽  
Vol 10 (21) ◽  
pp. 7418
Author(s):  
Grégoire Corradi ◽  
Jean-Jacques Sinou ◽  
Sébastien Besset
Keyword(s):  
Acoustic Radiation ◽  
Synthesis Method ◽  
Element Model ◽  
Signal Decomposition ◽  
Reduced Models ◽  
Wavelet Representation ◽  
Acoustic Pattern ◽  
Squeal Noise ◽  
Friction Induced Vibration ◽  
Multiresolution Signal Decomposition

This paper is devoted to discussion of the efficiency of reduced models based on a Double Modal Synthesis method that combines a classical modal reduction and a condensation at the frictional interfaces by computing a reduced complex mode basis, for the prediction of squeal noise of mechanical systems subjected to friction-induced vibration. More specifically, the use of the multiresolution signal decomposition of acoustic radiation and wavelet representation will be proposed to analyze details of a pattern on different observation scales ranging from the pixel to the size of the complete acoustic pattern. Based on this approach and the definition of specific resulting criteria, it is possible to quantify the differences in the representation of the acoustic fields for different reduced models and thus to perform convergence studies for different scales of representation in order to evaluate the potential of reduced models. The effectiveness of the proposed approach is tested on the finite element model of a simplified brake system that is composed of a disc and two pads. The contact is modeled by introducing contact elements at the two friction interfaces with the classical Coulomb law and a constant friction coefficient. It is demonstrated that the new proposed criteria, based on multiresolution signal decomposition, allow us to provide satisfactory results for the choice of an efficient reduced model for predicting acoustic radiation due to squeal noise.

Active Control of Vibration and Noise Radiation from Fluid-Loaded Cylinder using Active Constrained Layer Damping

2002 ◽  
Vol 8 (6) ◽  
pp. 877-902 ◽  
Author(s):  
W. Laplante ◽  
T. Chen ◽  
A. Baz ◽  
W. Sheilds
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Acoustic Radiation ◽  
Sound Radiation ◽  
Element Model ◽  
Water Tank ◽  
Constrained Layer Damping ◽  
Active Constrained Layer Damping ◽  
Active Constrained Layer ◽  
Surrounding Fluid

Vibration and sound radiation from fluid-loaded cylindrical shells are controlled using patches of Active Constrained Layer Damping (ACLD). The performance and the enhanced damping characteristics via reduced vibrations and sound radiation in the surrounding fluid is demonstrated both theoretically and experimentally. A prime motivation for this work is the potential wide applications in submarines and torpedoes where acoustic stealth is critical to the effectiveness of missions. A finite element model is also developed to predict the vibration and the acoustic radiation in the surrounding fluid of the ACLD-treated cylinders. The developed model is used to study the effectiveness of the control and placement strategies of the ACLD in controlling the fluid-structure interactions. A water tank is constructed that incorporates test cylinders treated with two ACLD patches placed for targeting specific vibration modes. Using this arrangement, the effectiveness of different control strategies is studied when the submerged cylinders are subjected to internal excitation, and the radiated sound pressure level in the water is observed. Comparisons are made between the experimental results and the theoretical predictions to validate the finite element model.

A Study of the Effects of Negative Friction-Speed Slope on Brake Squeal

1995 ◽  
Author(s):  
Yongbin Yuan
Keyword(s):  
Degrees Of Freedom ◽  
Element Model ◽  
Compression Modulus ◽  
Brake Squeal ◽  
Single Degree Of Freedom ◽  
Beam Elements ◽  
Negative Friction ◽  
Unstable Vibration ◽  
Almost All ◽  
Friction Induced Vibration

Abstract Brake squeal is caused by friction-induced vibration of brake systems. It may take place due to several possible mechanisms. The inverse variation of friction coefficient with relative sliding speed, also called negative μ-v slope, is one of them. Although it has been demonstrated in many articles that negative μ-v slope can cause unstable vibration for systems with a single degree of freedom (d.o.f.), its effects on multi-d.o.f. brake systems are not yet well understood. Since almost all types of friction materials for automotive brakes exhibit negative μ-v slope under certain conditions, it is important to clarify its role in brake squeal. The current study incorporates the negative μ-v slope friction law into a Finite element model for disc brake systems. The rotor and pads are modeled by beam elements, and the caliper is represented by a rigid body with two degrees of freedom. The effects of negative μ-v slope on the vibration stability of a brake system are studied along with several parameters including friction level, lining compression modulus, and steelback thickness.

scholarly journals Lateral vibration control of a shafting-hull coupled system with electromagnetic bearings

2018 ◽  
Vol 38 (1) ◽  
pp. 154-167 ◽  
Author(s):  
Hui Qin ◽  
Hongbo Zheng ◽  
Wenyuan Qin ◽  
Zhiyi Zhang
Keyword(s):  
Frequency Response ◽  
Acoustic Radiation ◽  
Synthesis Method ◽  
Coupled System ◽  
Lateral Vibration ◽  
Vibration Transmission ◽  
Lateral Vibrations ◽  
System A ◽  
Vibration Responses ◽  
Stiffness And Damping

In order to suppress lateral vibration transmission and reduce acoustic radiation of a shafting-hull coupled system, a new approach using electromagnetic bearings in the shafting system is proposed. The dynamic characteristics of the electromagnetic bearings, especially the equivalent stiffness and damping as well as the applicable scope of linearization of the electromagnetic bearings, are analysed at first. With the equivalent parameters, a dynamic model of the shafting-hull coupled system is established subsequently by using the frequency response synthesis method to derive frequency response functions associated with the lateral vibrations. Finally, the influence of the control parameters of the electromagnetic bearings on vibration transmission in the shafting-hull system is studied. Analysis results indicate that lateral vibration responses are suppressed significantly when electromagnetic bearings are introduced into the shafting-hull system, and as a result, sound radiation of the system is reduced, which demonstrates that the proposed approach is effective in controlling vibration transmission in the shafting system.

Acoustic Radiation Simulation of Marine Sliding-Thrust Bearing Shell Based on SYSNOISE

2011 ◽  
Vol 291-294 ◽  
pp. 1961-1964
Author(s):  
Guang Liang Zhao
Keyword(s):  
Dynamic Analysis ◽  
Boundary Element ◽  
Thrust Bearing ◽  
Acoustic Radiation ◽  
Element Model ◽  
Sound Power ◽  
Supporting Structure ◽  
Radiated Sound ◽  
The Impact ◽  
Radiated Sound Power

This paper takes marine Kingsbury sliding thrust bearing as the research object and conducts the finite element dynamic analysis with the aid of ANSYS software. On this basis, the acoustic boundary element model of a sliding thrust bearing shell is established with the ANSYS dynamic analysis results as the boundary excitation conditions. Besides, the radiated sound power of the shell is calculated by indirect boundary element method in SYNOSISE software. The influence of different condition parameters on the radiated sound power of the shell is perceived through the analysis of several rotation-thrust conditions. As for the special structure of this kind of sliding-thrust bearing, this paper states the impact of the supporting structure performance parameters, the pad number and damp of shell on the shell radiated sound power. The optimized measure for the supporting structure and the plan concerning the pad number’s selection lays the theoretical basis for damping and noise-reducing research on marine sliding-thrust bearing and its rotor system.

Sign in / Sign up

Export Citation Format

Share Document