Brake Squeal Analysis Using Harmonic Eigenmode Screening
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Solution Overview
Problem
Current numerical methods for predicting brake squeal noise are inefficient, as they only provide information around an initial state of static equilibrium, fail to prioritize instabilities, and are computationally expensive, making it difficult to reduce development costs and manufacturing nuisances in brake systems.
Innovation Solution
A method that reviews physical parameters of a brake system, identifies eigenmodes corresponding to instabilities, and performs harmonic decomposition to reduce squealing noise by linearizing contact forces with respect to displacement and speed, allowing for efficient identification of squeal generation factors without long calculation times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If classical complex modal analysis is used to evaluate brake squeal, then instability information around static equilibrium can be obtained, but the method cannot prioritize instabilities and requires excessive computation time
Solution Approach 1:
The patent segments the brake system into discrete contact elements at friction interfaces, allowing independent linearization of each contact element. This segmentation enables efficient computation while maintaining accuracy in identifying unstable modes, resolving the contradiction between precise instability identification and computation time
Solution Approach 2:
The patent changes the approach from global nonlinear analysis to local linearization parameters at each contact element. By linearizing contact forces independently for each contact element based on local displacement and velocity, the method achieves computational efficiency without sacrificing the ability to identify squeal-generating instabilities
2Loss of information
If harmonic equilibrium methods are used to analyze brake system instabilities, then more comprehensive instability information can be obtained, but convergence difficulties arise due to impacts between disc and pads
Solution Approach 1:
The patent applies preliminary anti-action by pre-linearizing contact forces at each contact element before performing harmonic analysis. This preliminary linearization prevents convergence issues that would otherwise arise from nonlinear impact behaviors between disc and pads, while still capturing comprehensive instability information
Solution Approach 2:
The patent introduces an intermediary linearized contact force model that mediates between the nonlinear impact behavior and the harmonic equilibrium analysis. This intermediary model allows comprehensive instability information to be obtained without the convergence difficulties caused by direct nonlinear impact modeling
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the efficient identification of squeal generation factors, reducing decision-making time in product development and producing brake systems with less noise, while maintaining reasonable computation times for industrial use.
Implementation Method 1
The linearized stiffness matrix, obtained before performing the complex modal analysis, is asymmetrical due to friction phenomena
Implementation Method 2
for each amplitude imposed during the scan, perform by computer a decomposition of the brake system into harmonics by linearizing the contact forces with respect to displacement and velocity
Data Source
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AI summary
Method for optimizing a brake system, comprising at least the steps of - reviewing (100, 110) possible values of at least one physical parameter - for each value reviewed and for a predetermined point of static equilibrium of the brake system, searching for and identifying by computer (1000, 1100) the different natural modes of the brake system corresponding to instabilities, - for each identified natural mode, imposing during a computer scan different vibratory amplitudes ( 2000, 2800), and for each imposed amplitude, carry out a computer breakdown of the brake system into harmonics (2100-2400) having linearized (2500) the contact forces with respect to displacement and speed to identify (2600, 2700) unstable eigenmodes, - choosing (3000) a value of the physical parameter as a function of the unstable eigenmodes identified to reduce the squealing noise of the brake system.