U.P.B. Sci. Bull., Series D, Vol. 76, Iss. 4, 2014 ISSN 1454-2358 SQUEEZE EFFECTS OF AN INFINITELY LONG, RIGID CYLINDER ON A HIGHLY COMPRESSIBLE POROUS LAYER IMBIBED WITH LIQUID Mihaela RADU 1 , Traian CICONE 2 Ex-poro-hydrodynamic (XPHD) lubrication describes the lifting effect produced by the flow of fluid through an extremely compressible porous material subjected to compression. Studies published recently on the behaviour of such materials, for various configurations, reveal good potential in shock absorption. The present study addresses the case of an infinitely long cylinder that impacts a highly compressible porous layer interposed between the cylinder and a rigid plane. Based on a 1D flow model, the lift effects for squeeze at constant speed, constant force and impact loading, respectively are analyzed. Keywords: XPHD lubrication, porous layer, squeeze, cylinder on plane, impact 1. Introduction Intuitively, we can visualize a porous medium as a complex system of cavities or capillaries, arbitrary distributed in a form that resembles a labyrinth. The fundamental problem of porous media is the complexity of the flow through this maze of capillaries which is practically impossible to solve analytically, and which will not describe globally the phenomena. This is why a macroscopic approach of the behaviour of the fluid inside the material is preferred. A new mechanism of lubrication, based on highly compressible porous layers imbibed with liquids, was observed and studied by M. D. Pascovici [1] under the name of ex-poro-hidrodynamic (XPHD) lubrication. Similar results have been obtained in parallel by S. Weinbaum and R. Crawford, for porous materials with extremely high porosities imbibed with gases [2], [3]. Recently, the research team led by B. Bou-Saïd has published a series of papers on similar effects for planar configuration (disk-on-plane) where the effects of complex rheological fluid properties and fluid inertia have been investigated analytically and numerically [4], [5]. The lift effect is explained by the resistance to flow of the fluid forced to be expelled through the pores of the material subjected to compression. This 1 Assist., Department of Machine Elements and Tribology, University POLITEHNICA of Bucharest, Romania, e-mail: mihaela.radu@upb.ro 2 Prof., Department of Machine Elements and Tribology, University POLITEHNICA of Bucharest, Romania