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Development of a Multidisciplinary Methodology for Brake Disc Design
Published May 23, 2004 by Society of Automotive Engineers of Korea in South Korea
This paper shows the methodology used in the development of brake rotor, from the geometry design until the realization of functional test and validations, relating several disciplines.
The braking system, and additionally the brake disc, is a safety component. For this reason, its design must be done very carefully. This brake part must satisfy very severe mechanical and thermal accomplishments.
With the actual trend in the automotive industry of weight reduction, decreasing the unsprung mass, the brake disc is one of the components more susceptible of redesign.
Additionally, with the decrease of the sonority and vibration in other vehicle systems, it conceives that the braking system is one of the devices that originate great problems from the acoustic and vibration point of view.
All these aspects must be considered during the geometry design of the rotor and during the choice of the chemical composition of the gray cast iron.
The geometric trend in brake disc goes to the improvement of the fluid-mechanical behavior, looking for the increase of the disc cooling ability by forced convection and the reduction of the thermo-mechanical distortions.
Thinking in the chemical composition, the trend is the use of gray cast iron with high content in Carbon, by its thermal and mechanical properties, although other options have been studied as Aluminum Metal Matrix Composites or Carbon/Carbon disc.
In the different stages of the development, the most advanced techniques are used. Software for Mechanical, Thermal, Fluid-mechanical and Casting Analysis are employed in the simulations. During the experimental phases, Dynamometer, Anemometer, Infrared Scanner, Specifics Transducers, etc., are utilized too.
For the design, the Software CATIA is used. During the discretization of the models utilized is the software ANSA and HYPERMESH. FLUENT is employed for the Fluid-mechanical analysis. In the resolution of the thermo-mechanical problem utilized has been the software MARC/MENTAT. NASTRAN/PATRAN is used for the realization of the modal analysis. MAGMA Soft analyzes the problem of the casting of the different models.
For the validation and functional tests, a braking system dynamometer and a bench of fluid-mechanical test are employed. Measure equipment of different applications fields are utilized: DANTEC Anemometer, μ-Epsilon displacement sensor, DATATEL telemetry, Infrared Scanner, Pressure, Force and Temperature sensors, microphones, accelerometers, etc.
The brake disc development needs multidisciplinary work equipment. It is necessary to have a deep knowledge in disciplines as different as Mechanics, Thermodynamics, Metallotechnics, Tooling, Acoustics and Vibrations, Electronics, etc. The Active Safety Area of Fundación Cidaut, has developed this methodology for Lingotes Especiales (Spain), a foundry what supply brake rotors to the main European car manufacturers (PSA, General Motor, RENAULT, FORD, VW, etc.).