Investigation of PDC Cutter Interface Geometry Using 3D FEM Modelling

Abstract

Polycrystalline Diamond Compact (PDC) cutters have been popularly used in recent times due to their resistance against mechanical and thermal wear. This paper was focused on interface geometries between the substrate and the diamond table. Various types of interfaces were designed, to investigate how different interface geometries influence distribution of stress and strain under shear loading. The interface geometries examined in this paper included castle interface, dent interface, honeycomb interface and chase interface. Parallel to the interface, shear loading was applied to the top of diamond table to mimic the shear loading component from the rock cutting. To apply the shear loading, two locations were considered for each of the geometries. These locations differed depending on the interface features. Stress and strain distribution and values across different interface geometries were analysed with the aid of 3D Finite Element Method (FEM). The numerical simulations indicated that stress and strain magnitudes and distribution patterns varied in relation to different geometries. Some substrates showed relatively lower plastic strain representing higher durability of the geometries. Concentration of stress and strain distribution showed the areas where one could expect weakness. It also implies that rotating the PDC cutter assemblies around their cylindrical axis helps avoiding fatigue of interface elements in regions of high stress concentration; and thus, preventing premature failure of interface elements.