CARBON/CARBON FRICTION PAIR PERFORMANCE - TOWARDS AN UNDERSTANDING OF SURFACE MORPHOLOGY AND COEFFICIENT OF FRICTION VARIATION IN A HIGH ENERGY CLUTCH APPLICATION

摘要

Carbon/carbon friction pair technology offers many advantages in applications characterised by low weight, minimal package space and high energy density. In certain applications, knowledge of torque output and its fluctuation during the period of friction pair engagement is crucial to the overall performance of the vehicle in question. This paper presents initial findings from work that aims to establish a relationship between interface temperature, surface morphology, friction levels and torque capacity of a friction pair used within a dry, multi-plate clutch. The design of a purpose built Single Clutch-plate Interface Dynamometer that replicates the conditions of normal load, sliding speed and energy dissipation encountered in the multi-plate system, is used to provide a means through which the fundamentals of a single friction- pair interface can be investigated is discussed. Results from surface scanning techniques are also presented to illustrate the extent of hot banding phenomena. A one-dimensional thermal model of a single clutch-plate pair is used along with a Taguchi design of experiment analysis to gain understanding of the levels of coupling between the maximum surface temperature and each of the system parameters. Finally, the initial development of a coupled thermomechanical axisymmetric finite element analysis which is used to model banding effects and assess the potential impact of such effects on the torque capacity of the friction pair is presented.