The friction and wear of Kevlar 49 sliding against aluminium at low velocity under high contact pressures

The friction and wear behaviour of Kevlar 49 sliding against aluminium unde r large contact pressures at low sliding velocities was examined. Kevlar 49 on aluminium friction is measured using yarns on capstans, and compared wi th literature results for Kevlar 49 on itself. A modified version of Howell 's equation is presented in terms of stresses, tau = a sigma(beta), to allo w finite element modelling of rope terminations. For Kevlar 49-on-aluminium this takes the form tau(s) = 0.099 sigma(0.91) and T-d = 0.095 sigma(0.91) . Kevlar 49-on-Kevlar 49 friction is not so critical in the mechanics of th e terminations as it is greater (mu --> 0.22 at high pressures). Medium sca le tests using yarns of 1000 filaments around capstan discs of radii 10-80 mm were performed; these are compared with large scale tests on 6 and 60 to nne rope terminations. In both situations the wear rate is calculated from the number of cycles to failure for a given severity regime. The wear rate is found to be directly proportional to the normal load for five orders of magnitude of load (6-40000 N), so Kevlar 49-on-aluminium abrasion can be ex pressed in terms of the Archard wear equation. The dimensional wear coeffic ient is found to depend strongly on the amplitude of slip present, rising f rom 1.0 x 10(-5) mm(3)(Nm)(-1) at 40 mu m to 1.0 x 10(-2) mm(3)(Nm)(-1) at 3 mm peak to peak displacement. (C) 1999 Elsevier Science S.A. All rights r eserved.