Maintaining appropriate levels of disc-pad interface temperature is critical for the overall operating effectiveness of disc brakes and implicitly the safety of the vehicle.Measurement and prediction of the distribution and magnitude of brake friction interface temperatures are difficult. A thermocouple method with an exposed hot junction configuration is used for interface temperature measurement in this study.Factors influencing the magnitude and distribution of interface temperature are discussed. It is found that there is a strong correlation between the contact area ratio and the interface maximum temperature. Using a designed experiment approach, the factors affecting the interface temperature, including the number of braking applications, sliding speed, braking load and type of friction material were studied. It was found that the number of braking applications affects the interface temperature the most. The real contact area between the disc and pad, i.e. pad regions where the bulk of the kinetic energy is dissipated via friction, has significant effect on the braking interface temperature. For understanding the effect of real contact area on local interface temperatures and friction coefficient, Finite Element Analysis (FEA) is conducted. It is found that the maximum temperature at the friction interface does not increase linearly with decreasing contact area ratio. This finding is potentially significant in optimising the design and formulation of friction materials for stable friction and wear performance. Tave Change of average temperature of the brake pad body (°C) DoE A statistical design of experiments approach emf ElectroMotive Force WIRE An exposed wire thermocouple configuration for brake disc/pad interface temperature measurement RUB A rubbing thermocouple for brake disc surface temperature measurement Key words

The performance of resin bonded composite friction materials in a particular brake design is strongly dependent upon the dissipation of frictional heat from the interface. This energy transformation has been studied using finite element techniques for a simulation of the braking friction process in an annular disc brake, which combines both brake performance and brake temperature analysis and avoids many of the assumptions necessary in conventional analyses. Negligible amounts of energy interchange, compared with the total kinetic energy dissipated, arise from chemical reactions within the friction material, but the formation of surface layers and interfacial wear products do have a signijicant effect upon heat transfer from the interface. Calculated temperature distributions over indioidual brake applications indicate that interface contact resistance leads to different temperatures at the surfaces of disc and lining so that heat partition between the two mating bodies cannot realistically be assumed constant under braking conditions. The distribution of frictional heat generation over the interface is dependent upon interface pressure distribution and is therefore also affected by material wear and thermal expansion. These effects are incorporated in the analysis, and calculated temperature, interface contact and pressure, and wear distributions are compared with observed and measured experimental results from an annular brake rig. 69/84 Q IMechE 1984

The nature of the contact and pressure at the interface between thefriction material pad and the disc rotor of a 'spot'-type disc brake affects the performance of a brake in terms of torque, temperature distributions and wear. Interface contact and pressure distributions have been predicted for a particular design of floating caliper passenger car disc brake, using three-dimensional finite element analysis under static and dynamic brake actuation conditions. The influence of friction material compressibility, pad backplate thickness, co&cient of friction, caliper flexure, disc stiflness and actuating piston contact with the piston bore on the interface pressure distribution is examined. The eflect upon brake performance is discussed in terms of 'centre of pressure' and corresponding braking torque, and in terms of observed eflects such as temperature and wear distribution. The results confirm that in order to ensure consistent disc brake pe$ormance the interface pressure distribution should be carefully controlled by designing in mechanical rigidity, compliant friction materials and minimum compliance during brake operation.

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This paper describes how hydraulic and water quality data from a distribution network may be used to provide a more efficient leakage management capability for the water industry. The research presented concerns the application of artificial neural networks to the issue of detection and location of leakage in treated water distribution systems. An architecture for an Artificial Neural Network (ANN) based system is outlined. The neural network uses time series data produced by sensors to directly construct an empirical model for predication and classification of leaks. Results are presented using data from an experimental site in Yorkshire Water's Keighley distribution system.