Influence of Al2O3 particles in composite material on determined with FEM stresses and stains in paring with cast iron.
Andrzej Posmyk, Henryk Bakowski
Quarterly No. 1, 2009 pages 29-33
DOI:
keywords: reinforcing particle, distribution of stresses and strains, composite, cast iron, wear
abstract The attempt to explain of the mechanism of wear in pairing cast iron EN-GJL-350/composite W6A.15D using of Finite Elements Methods (FEM) has been presented in this paper. As a result of conducted tribological and metallographic investigations the coefficient of friction, wear rate and stereological parameters of investigated material have been determined. Based on those results, the model of pairing has been elaborated and simulating calculations have been conducted. The assumptions for that model are as follows: the average diameter of reinforcing particles d = 15 um, average distance between particles is 25 um, the surface fraction of alumina particles AN = 625 mm−2, the frictionless case (u = 0) and friction in air (u = 0.3). The friction force acting on every particle has been divided by nine (one part per one mesh) what causes homogenous stresses distribution. The models of pairing without and with friction forces has been elaborated. Simulation calculations have shown that the maximum of stresses is in a cast iron on the reinforcing phase edge and in a matrix material, on the border between alumina particles and matrix. The maximum stresses (65 MPa) are 20 times larger then the given load (3 MPa). The first maxi- mum helps to explain the wear intensity of cast iron and the second one helps to explain why some particles are removed from the matrix and make damages of the contact surfaces during the wearing in stage of the sliding. The hard alumina particles protruding over the matrix material cause the wear of sliding partner. Normal load acting on sliding parts causes plastic deformations of cast iron resulting in its intensive abrasion wear. Friction force acting tangential to the rubbing surface causes a formation of a rotation moment on the reinforcing particle that tries to rotate the particle. When the rotating moment is greater then the adhesion between matrix material and particle cams to hers removal from the matrix. One removed ceramic particle causes great damages in sliding surfaces of cast iron and aluminium alloy matrix.