A finite element model of the elastic planar and spherical contact with hard and soft coatings

Abstract

A finite element model of a rigid sphere contact with a deformable coating flat was used to study the elastic contact between the soft and hard coatings. Meanwhile, the contact of a rigid flat and a deformable coating sphere under the same condition was used for comparison. The contact area, load, interference, and maximum equivalent von Mises stresses in the coating system were normalized by the corresponding elastic contact parameters. The empirical expressions for the above two models which contained a wide range of the mechanical and geometric properties in soft and hard coatings were established by fitting the numerical results. The changes in the location of the maximum von Mises stress distribution in the models’ soft and hard coatings were compared when the displacement loads were used. The relationships between the dimensionless maximum von Mises stress on the substrate and coating and the dimensionless contact parameters were provided when the elastic limit (plastic yield onset) occurred. The range of the dimensionless coating thickness which led to the onset of plastic yield in the coating was determined when the rigid sphere was contacting with the deformable coating flat.