In this paper, some new elastohydrodynamic Reynolds-rod models are posed to
obtain the existence of solution (the lubricant pressure and the elastic r
od displacement). More precisely, a sign restriction on fluid pressure for
cavitation modelling and different unilateral conditions on the rod displac
ement associated with a rigid structure coating are formulated in terms of
coupled variational inequalities. The particular hinged or clamped boundary
conditions on the rod displacement require different techniques to prove t
he existence of solution. Besides nearly linear coupled problems, two non-l
inear rod problems including curvature effects are analysed. Mainly, regula
rity results and L-infinity estimates for the solution of variational inequ
alities and fixed-point theorems lead to the existence results for the vari
ous coupled models. Copyright (C) 2001 John Wiley & Sons, Ltd.