Vibration energy and repeated-root modes of disc rotor for high-frequency brake squeal

2018 ◽  
Vol 233 (2) ◽  
pp. 363-378
Author(s):  
Pu Gao ◽  
Yongchang Du ◽  
Paul D Walker
Keyword(s):  
High Frequency ◽  
Coupling Model ◽  
Equilibrium Analysis ◽  
Vibration Energy ◽  
Brake Squeal ◽  
Modal Composition ◽  
Brake Pads ◽  
Transfer Path ◽  
Composition Method ◽  
Energy Equilibrium

In this paper, the generation mechanism of high-frequency brake squeal is revealed from the perspective of vibration energy. Based on a closed-loop coupling model, vibration energy transfer paths at the friction coupling interface between brake pads and disc are derived. Vibration energy equilibrium analysis is used to verify the reliability and accuracy of the derivation and the presented result demonstrates that vibration energy transferred from disc rotor to pads is the dominant transfer path. It is also demonstrated that the disc rotor is the key substructure affecting high-frequency brake squeal. As the disc rotor is axisymmetric, its repeated-root modes may lead to unreasonable calculated results by using the substructure modal composition method for analyzing the brake squeal. In this study, these repeated-root modes are processed by using a modified substructure modal composition method to obtain one unique integrated substructure modal composition coefficient of each disc repeated-root modes. Finally, the presented method is applied to analyze the brake squeal in the 13 kHz frequency band. The results easily identify the key vibration modes of the disc affecting high-frequency brake squeal, verifying the reliability of the presented method.

High-frequency vibration energy harvesting from repeated impulsive forcing utilizing intentional dynamic instability caused by strong nonlinearity

2016 ◽  
Vol 28 (4) ◽  
pp. 468-487 ◽  
Author(s):  
Kevin Remick ◽  
D Dane Quinn ◽  
D Michael McFarland ◽  
Lawrence Bergman ◽  
Alexander Vakakis
Keyword(s):  
Energy Harvesting ◽  
Mechanical System ◽  
High Frequency ◽  
Large Amplitude ◽  
Electromechanical Coupling ◽  
Dynamic Instability ◽  
Vibration Energy ◽  
Primary System ◽  
Vibration Energy Harvesting ◽  
Strongly Nonlinear

The work in this study explores the excitation of high-frequency dynamic instabilities to enhance the performance of a strongly nonlinear vibration-based energy harvesting system subject to repeated impulsive excitations. These high-fraequency instabilities arise from transient resonance captures (TRCs) in the damped dynamics of the system, leading to large-amplitude oscillations in the mechanical system. Under proper forcing conditions, these high-frequency instabilities can be sustained. The primary system is composed of a grounded, weakly damped linear oscillator, which is directly subjected to impulsive forcing. A light-weight, damped nonlinear oscillator (nonlinear energy sink, NES) is coupled to the primary system using electromechanical coupling elements and strongly nonlinear stiffness elements. The essential (nonlinearizable) stiffness nonlinearity arises from geometric and kinematic effects resulting from the traverse deflection of a piano wire coupling the two oscillators. The electromechanical coupling is composed of a neodymium magnet and inductance coil, which harvests the energy in the mechanical system and transfers it to the electrical system which, in this present case, is composed of a simple resistive element. The energy dissipated in the circuit is inferred as a measure of energy harvesting capability. The large-amplitude TRCs result in strong, nearly irreversible energy transfer from the primary system to the NES, where the harvesting elements work to convert the mechanical energy to electrical energy. The primary goal of this work is to numerically and experimentally demonstrate the efficacy of inducing sustained high-frequency dynamic instability in a system of mechanical oscillators to achieve enhanced vibration energy harvesting performance. This work is a continuation of a companion paper (Remick K, Quinn D, McFarland D, et al. (2015) Journal of Sound and Vibration Final Publication) where vibration energy harvesting of the same system subject to single impulsive excitation is studied.

Reduction of Vibration and Noise Generated by Planetary Ring Gears in Helicopter Aircraft Transmissions

1973 ◽  
Vol 95 (4) ◽  
pp. 1149-1158 ◽  
Author(s):  
Thomas Chiang ◽  
R. H. Badgley
Keyword(s):  
High Frequency ◽  
Narrow Band ◽  
Vibration Energy ◽  
Ring Gear ◽  
Noise Sources ◽  
Rotor Drive ◽  
Design Changes ◽  
Planetary Ring ◽  
Gear Meshes ◽  
Very High

Rotor-drive gearboxes are major noise sources in helicopter aircraft. Narrow-band examination of this noise often indicates the presence of several or more very high, narrow noise peaks, which are located at gearbox mesh frequencies or their multiples. Important exceptions are sideband noise components, located so near the main signal component as to be indistinguishable except by very narrow band reduction. Noise of this type is most effectively treated through a systematic study of the flow of high-frequency vibration energy in the drive train. Such studies should examine the mechanism by which gear meshes generate vibrations, and the vibration response of the gearbox components which support the gears. Results of such calculations are presented for the planetary reduction ring-gear casing elements in the Boeing-Vertol CH-47 forward rotor-drive gearbox and the Bell UH-1D main rotor-drive gearbox. The calculations indicate logical reasons why noise is generated. Typical ring-gear casing design changes are examined for noise reduction.

Conceptual Design Method for Reducing Brake Squeal in Disk Brake Systems Considering Unpredictable Usage Factors

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Toru Matsushima ◽  
Kazuhiro Izui ◽  
Shinji Nishiwaki
Keyword(s):  
Conceptual Design ◽  
High Performance ◽  
Design Method ◽  
Contact Stiffness ◽  
Low Frequency ◽  
Optimization Method ◽  
Design Stage ◽  
Brake Squeal ◽  
Brake Pads ◽  
Disk Brake

Minimizing brake squeal is one of the most important issues in the development of high performance braking systems. Furthermore, brake squeal occurs due to the changes in unpredictable factors such as the friction coefficient, contact stiffness, and pressure distribution along the contact surfaces of the brake disk and brake pads. This paper proposes a conceptual design method for disk brake systems that specifically aims to reduce the occurrence of low frequency brake squeal at frequencies below 5 kHz by appropriately modifying the shapes of brake system components to obtain designs that are robust against changes in the above unpredictable factors. A design example is provided and the validity of the obtained optimal solutions is then verified through real-world experiments. The proposed optimization method can provide useful design information at the conceptual design stage during the development of robust disk brake systems that maximize the performance while minimizing the occurrence of brake squeal despite the presence of unpredictable usage factors.

Stability Improvement of Brake Disc to Mode Coupling at High Frequency Squeal

2020 ◽  
Author(s):  
Anutcharee Khuntiptong ◽  
Chak Chantalakhana
Keyword(s):  
Field Test ◽  
High Frequency ◽  
Element Model ◽  
Modal Testing ◽  
Brake Disc ◽  
Complex Eigenvalue ◽  
Brake Pads ◽  
Locking Mechanism ◽  
Out Of Plane ◽  
Complex Eigenvalue Analysis

In this research study, the high-frequency squeal noise of a brake disc was found to occurred at a frequency of about 15 kHz. The potential root cause has been studied where mode frequency coupling and shape locking mechanism of brake disc and brake pads components are the main investigated topic. From the vehicle field test and the Dynamometer test, the braking condition, friction coefficient and braking pressure, have been confirmed to be used in numerical experiments. The updated finite element model (FEM) with the modal testing data of the existing brake components are formulated for the Complex Eigenvalue Analysis (CEA). In this study, the modification is based on in-board and out-board cheek thickness of the brake disc. Two of nine modifications of the brake disc cheek thickness are proposed with the method of separation the brake disc out-of-plane and in-plane modes and the method of avoiding shape locking between the brake disc and the brake pads modes. The constructed prototypes are verified with the vehicle field test and well agreed with the CEA.

Effect of pad shapes on high-frequency disc brake squeal

2016 ◽  
Vol 72 (4) ◽  
pp. 354
Author(s):  
Yongchang Du ◽  
Dihua Guan ◽  
Xiaofeng Wang
Keyword(s):  
High Frequency ◽  
Disc Brake ◽  
Brake Squeal
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