A Dynamic Model for Dissipative Structures used in Bump-Type Foil Bearings

A gas bearing of bump-type foil comprises an underlying structure made of one or several strips of corrugated sheet metal covered by a top foil surface. The fluid film pressure thus needs to be coupled with the behavior of this structure for obtaining the equivalent bearing characteristics. The dynamic model of the bump-type foil structure is then of capital importance. The approach presented in this article is an extension of a previously presented static model considering the structure as a multidegree of freedom system. The continuous corrugated sheet is considered as a discrete one with two nodes and three degrees of freedom for each bump that are linked by linear springs. The hereby presented dynamic model is based on the time-domain integration of the elastic structure under a given load variation. Its efficiency is conditioned by the ability to deal with the discontinuities contained in the nonlinear Coulomb friction model. In order to avoid these numerical difficulties, the Coulomb friction forces...