When you brake, you may hear several different sounds. These noises vary in frequency and tonality. Some are higher-pitched, while others are lower-pitched and tonal. Depending on the frequency, you may hear a brake squeal or brake moan. Brake squeals tend to have higher frequency components, around 100 Hz, while brake moans and creep-groans tend to have lower frequency components, around 10 Hz.
High-frequency friction-induced tonal noise
When a car is braking, high-frequency friction-induced tonal noise may be heard. These noises can be either high or low in frequency, and are related to the in-plane resonances of the brake rotor. Brake squeals are often associated with high-frequency noises caused by braking.
The source of brake noise is the friction surfaces on the brake rotor and caliper assembly. However, the friction coupling also causes vibrational forces in other parts of the car, including knuckles, attached suspension, and the wheel well.
Nonlinearity
Brake noise is a major problem in automotive systems. It is an audible noise with a high frequency that is very annoying to human ears. Though many researchers have worked on this problem, no single solution has been proposed. To understand the causes of brake noise, it is necessary to use a mathematical model of the braking system. Using this model, we can study the nonlinearity of friction, kinematics, and clearance.
Nonlinearity can be categorized as local/distributed or weak/strong. The former refers to the degree of continuity in the nonlinear law, while the latter refers to the strength of its qualitative effect on the overall response. It can also be localized in space.
Stochastic models
Friction and brake noise are highly variable phenomena that are difficult to measure using standard brake noise and friction tests. The noise is caused by stochastic friction features, as well as time-varying material and interface properties. To solve the problem, researchers have created stochastic models to understand the noise produced by brake systems.
Stochastic models have the potential to improve CEA by improving the predictability of brake noise. They can also be used to develop proactive prevention strategies for braking problems. The current paper describes how stochastic analysis can be used to predict brake noise.
Dampening paste
One way to reduce electronic noise while braking is to apply dampening paste to your brake pads. This paste is a water-based compound that you apply to the metal part of your braking pads. It should be allowed to dry completely before you reinstall the pads. Once dry, the paste will become sticky and will reduce the noise when braking.
There are two types of dampening paste. One is made of butyl rubber and contains bituminous additives. It is formulated for soundproofing and silencing and is resistant to weathering and mechanical shocks. The other type of paste is flexible and can be applied to the outer plastic wheel arches.
Weared-out brake pads
The electronic noise that you hear when you brake your car is likely a sign of a worn-out brake pad. Typically, this noise is made by grinding or squealing noises. This is caused by the metal brake pad plate pressing against the metal brake rotor. If this is a constant noise, you should have your brakes checked.
It is also a symptom that your wheel bearings are not balanced or that your brake pads are leaking brake fluid. In both cases, you should change the brake fluid as soon as possible. The noise may be so annoying that it interferes with your braking and can cause you to stop driving.
Worn-out rotor discs
Worn-out rotor discs can cause a squealing, grinding, or hissing noise when braking. Fortunately, resurfacing them can fix the noise. The rotor’s surface can be made smoother with the use of a special coating. Ideally, the surface finish should be 60 microinches or less.
The first step is to check for surface rust. If your rotors are rusting, they will become uneven and will create raised spots. This will reduce brake performance and require more frequent replacement of brake pads.
