Temperature analysis of a brake disc
The development of vehicles is a very complex task and has a long tradition in Germany. Cars have become a part of our everyday life and always have to meet higher safety standards. Thereby the components have to pass various static and dynamic tests. In the braking system, as one of the most important parts for vehicle safety, the temperature, as on other components, plays an important role. The temperature distributions and the resulting changes in structure and function can be calculated by using FEM analysis.
Task
The distribution of the temperature on the disc is decisive for functionality. When the temperature gets to high, the hole braking system loses effectiveness. So the aim is to make the heat transfer more effective to prevent excessive heating. This can be achieved in different ways: variation of the geometry, use of specific materials or adaption of the braking interval.
Solution
To solve these problems, we studied a brake model in terms of the material, the geometry and the temperature as a function of time. Both heat conduction in the material and convection to the environment as well as the description of the torque of the disk are described with our model. Assuming that the delay is only effected by the friction of the brakes, the heating power can be determined at the contact surfaces of the brake. The model also includes heat conduction in the brake disc and the brake block, which is realized by using the heat transfer equation (respectively diffusion equation).
Results
In this test case, the brake is held for two seconds and then released. Figure 1 shows the temperature profile after 1.4 seconds and Figure 2 after 4 seconds. Holes in the disk effect a reduction of the internal temperature in the range of more than 50 ° C. Due to excessive increase in the temperature, the disc loses its efficiency. In consideration of material and structural properties a brake disk geometry using FEM can be developed that ensures optimum temperature distribution.
Advantages of FEM Simulation
- Simple time-saving tests with varying geometries and scenarios
- Consideration of different temperature ranges can easily be calculated
- In addition to thermal also other physical and chemical properties can be analyzed
