Kinematics of transverse real roughness in elastohydrodynamically lubricated line contacts using Fourier analysis

A model is presented that facilitates prediction of the transient solution for the pressure and film thickness in an elastohydrodynamically lubricated line contact for the case of arbitrary surface microgeometry (roughness) u nder the assumption of Newtonian lubricant behaviour and small roughness am plitude. In the model the two parts of the transient solution (particular i ntegral and complementary function) are calculated for each Fourier compone nt of a surface real roughness and combined to obtain the complete transien t solution. As no time-consuming numerical simulations are required, the co mputational scheme forms a simple and efficient tool for use in a practical engineering environment. To validate the approach, first simple cases such as single dents and harmonic waviness were considered. The predictions obt ained for these cases are compared with the results of full numerical simul ations, showing good agreement. Subsequently the results obtained for a rea listic roughness profile are presented.