Analyzing Brake Materials

Brake materials operate in high friction and high energy environments, especially in automobiles. Prolonged use under these conditions can often cause brake materials to undergo degradation and wear.

To prevent brake materials from wearing to a level which is dangerous for the person operating the automobile, it is imperative that these materials are tested regularly. In this article, we look at ways in which brake materials are analyzed for the automotive industry.

What are Brake Materials?

Brake materials are materials used in brake system applications which are more resistant to friction than the “average” material. Brake materials are used in both automobiles and industrial equipment. There are a wide range of materials which can be used in brake applications. These include those with a metallic matrix, including monomer metal casting and powder metallurgy materials; those with a semi-metallic matrix, such as those composed of metal fiber, ceramic fiber, copper or iron; as well as materials with a non-metallic matrix, including modified resins and rubber; and organic friction materials.

How Do Brake Materials Work?

The brake materials are known as the brake pads in a braking system. When pressure is applied to the brake pedal in the automobile, two hydraulically operated pistons squeeze the brake pads towards the brake disk. When the pads, in which there are two, are squeezed, the pistons apply equal and opposite forces to the brake disk. This causes the brake disk to stop rotating, and in turn causes the vehicle to come to a halt.

Why Analyzing Brake Materials is Important

There are many factors to consider when analyzing brake materials. Due to the nature of the environment, high friction and excess wear are real concerns which can affect the performance of the brake material, the brake disk and the automobile as a whole. The brake disk is always composed of a harder material than the materials in the brake pad, and this can result in bumps appearing on the surface of the brake material. The high-speed forces involved with the brake disk can also cause the brake material to be sheared during operation.

However, the correlation between high amounts of friction and wear do not always match up. The frictional force is not always proportional to the force exerted by the load, and frictional coefficients of materials do not have a definitive value – instead their value is dependant upon the conditions at the time of use. The large number of variables involved with brake materials means that it is imperative that they are professionally maintained.

The cost of wear and friction can be low if properly maintained. However, if they are not well-maintained, the cost can be high because of brake failure. The cost of repeatedly replacing a broken brake disk is higher than that of regular maintenance. Aside from cost, brake disk failure is a major safety issue. If the brake disk fails while the vehicle is in motion, the automobile will not stop efficiently and can potentially lead to fatal accidents.

How Brake Materials are Analyzed

Brake materials are often analyzed through various tribological studies. Tribology is the study of interacting surfaces which includes the influence of friction, wear and lubrication on a material. Dynamometers have commonly been one of the traditional methods used for measuring the wear and friction exerted on brake materials. However, these instruments are both cost and time intensive and require both the brake pads and rotor to be in their final form. So, whilst they can be used to produce effective results for real-world environments under varying pressures, temperatures, speeds and deceleration, they are not able to provide rapid screening for the early stage of brake materials. Luckily, there are more versatile options available.

Products such as the UMT TriboLab^TM from Bruker are versatile pieces of equipment for tribological studies. It is used in a variety of tribology analysis and it has been recently developed using a modular concept. This concept now allows more functionality than ever before.

The new UMT TriboLab^TM now offers higher speeds, greater torques, greater force measurements, higher efficiencies and easier use than previous models. This new instrument is also capable of performing any tribology measurement at the nano and microscale.

This instrument is designed for real-world environments. Due to the high versatility obtained from the new advancements, the UMT TriboLab^TM can be used across a number of industries, including biomedical, microelectronics, paper, coatings, petrochemical, aerospace, automobile, engine, bearing, and fastener manufacturing.

References

• AZoM: https://www.azom.com/article.aspx?ArticleID=14745
• “Review on the friction and wear of brake materials”- Xiao X., et al., Advances in Mechanical Engineering, 2016, DOI: 10.1177/1687814016647300
• “Structural Design and Analysis of Disc brake in Automobiles”- Dakhil M. H., et al., 2014
• Bruker: https://www.bruker.com/products/surface-and-dimensional-analysis/tribometers-and-mechanical-testers/umt-tribolab/overview.html
• “Thermal Analysis of Disc brake made of Different Materials”- Abebe L., et al., SSRG International Journal of Mechanical Engineering, 2016

This information has been sourced, reviewed and adapted from materials provided by Bruker Nano Surfaces.

For more information on this source, please visit Bruker Nano Surfaces.

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