Contact and thermal analysis of transfer film covered real composite-steelsurfaces in sliding contact

For composite-steel surfaces in sliding contact an anisotropic numerical co ntact algorithm has been developed to study the 'layer type' problems. An F E contact analysis was applied to evaluate the contact parameters (real con tact area, contact pressure distribution and normal approach). The contact temperature rise was determined by using both a numerical thermal algorithm for stationary and a FE transient thermal technique for 'fast sliding' pro blems. The effect of a continuous transfer film layer (TFL), that had built up dur ing wear of the PEEK matrix material on the steel counterpart, was consider ed. Its thickness was assumed to be t=1 mum, and its material properties we re that of PEEK at room temperature or, in the case of frictional heating, at a temperature of 150 degreesC (i.e. above the glass transition temperatu re of the polymer matrix). Results are presented fur a spherical steel asperity, with/without TFL, sli ding over composite surfaces of different fibre orientation, and in additio n, for real composite-steel surfaces (based on measured surface roughness d ata) in sliding contact. The TFL has: an effect on the contact parameters e specially at higher operating temperatures (i.e. 150 degreesC); it results in the production of a larger contact area and a lower contact pressure dis tribution. The contact temperature rise is clearly higher if a TFL is prese nt. Due to the low thermal conductivity of PEEK, the TFL is close to the me lting state or it even gets molten within a small vicinity of the contact a rea. (C) 2000 Elsevier Science Ltd. All rights reserved.