Analytical and Numerical Study of Hard Rock Cutting With Roller Disc Cutters

Abstract

Steel roller discs are an efficient mechanical tool for cutting soft to medium strength rocks in both civil and mining projects. However, their application for hard rock cutting has been hindered since steel discs wear quickly and fail prematurely due to high concentrated stresses generated at the sharp corners and thin elements of the disc. To overcome this problem, the current generation roller discs comprises a steel shaft connected to a tungsten carbide (WC) disc. In other words, while the material of the disc itself is replaced by a stronger WC material, steel continues to be used for the shaft body. In this paper, to comprehend the influence of material parameters on the induced stresses inside different parts of a roller cutter, an analytical closed-form solution and a series of finite element (FEM) numerical studies are performed. By considering the problem as a traction boundary-value problem in an elastic domain, the analytical solution is based on the Airy stress formulation in Cartesian coordinates with a Fourier series representing the boundary conditions. The analytical result is developed for both plane stress and plane strain conditions, encompassing all possible loading configurations and shaft geometries. To verify the numerical models, these results are also compared with laboratory experimental data obtained from cutting granite using mini discs for the penetration range 1 to 3 mm.