FINITE ELEMENT ANALYSIS OF THERMOELASTIC INSTABILITY IN INTERMITTENT SLIDING CONTACT

摘要

A finite element model is developed for the frictionally excited thermoelastic instability problem in intermittent sliding contact with finite geometries and realistic friction materials. The existing analytical solutions are used to validate the method in several limiting cases. It is concluded that some caution must be taken for the commonly used strategy of assuming time-averaged factional heat generation for intermittent contact. The predictions made by the half-plane analytical solution that assumes thermally nonconductive and rigid frictional surface considerably overestimate the dimensionless critical speeds of realistic brake or clutch systems. Longer wavelength perturbations become unstable at a dimensionless sliding speed approaching zero, as opposed to the converged value of unity in the half-plane solution. A veraging the heat input over the entire circumference is appropriate only when the period of frictional contact is longer than that of separation. These results merit the use of the finite element method in more general applications involving intermittent contact.