Axisymmetric adhesive contact of multi-layer couple-stress elastic structures involving graded nanostructured materials

Abstract

Graded nanostructured (GNS) materials has attracted widespread attention in the recent years. The gradually changed microstructures and mechanical properties from the surface to the interior layer in graded nanostructured materials can improve the mechanical properties of the surface. The motivation of this research was to explore the effect of size effect, adhesion and gradient on the mechanical properties in contact between GNS coating and spherical indenter. The multi-layer couple-stress elastic structures is used to simulate the GNS coating with arbitrarily varying material properties. Based on the Maugis-Dugdale theory, the axisymmeric adhesive contact problem for multi-layer couple-stress elastic coated substrate system indented by spherical punch is converted to singular integral equations. Numerically calculation are conducted to obtain the influence of the characteristic material length, adhesion parameter and gradient index on the indentation, surface stress, surface displacement, total attraction force. The present results should be helpful for the understanding of the micro contact mechanics of GNS coating.