Identification of the friction under high pressure between an aggregate material and steel: Experimental and modelling aspects

The interface behaviour between steel and a quasi-brittle aggregate material is characterised up to normal pressures of the magnitude of 100 MPa. This article presents a new test enabling the behaviour of the interface to be studied whilst retaining the sample’s integrity. The experimental configuration having been retained consists in sliding a cylindrical sample of the material inside a steel tube, said tube acting both as a sliding surface and containment ring. The sample is pushed on one side and faces a spring on the other. The axial compression generates the interface pressure by Poisson effect. This originality of this assembly lies in the simultaneous application of normal pressure to the interface and of its relative motion. The assembly is placed in a quasi-static testing machine. The analysis is made by means of an analytical modelling of the test. This method enables the identification of the initial contact conditions (tightening of the sample), the friction coefficient and its dependence on the pressure. Numerical simulations of the test using a finite element method enables the analytical approach to be validated as well as the set of parameters identified depending on the normal pressure regimes.