The Thermal Characterisation of a Disc Brake Rotor at reduced scale with particular reference to PAD Aspect Ratio

An integral part of the development of a disc brake system is associated with the physical test of the foundation brake using a brake dynamometer. Testing undertaken at full scale is both costly and time consuming and recent work, for example Prabhu et al. (2015), has shown that reduced scale testing is capable of replicating the tribological conditions at the interface such that the thermal response of the rotor approaches that of its full scale counterpart. The same work also demonstrated experimentally the connection between pad aspect ratio and rotor response and this had been omitted from the formal scaling methodology. This paper extends the scaling theory to reflect the presence of pad aspect ratio through the use of a validated finite element model of the reduced scale brake. The results show that for the given reduced scale brake, there exists a pad aspect ratio at which the thermal response of the rotor is at a minimum. The conclusions drawn apply equally to the behaviour of the rotor at full scale.