Stress Evolution in Linear Cutting Tests: Laboratory and Numerical Methods

Abstract

Small-scaled linear cutting tests were first performed to study the influence of penetration on fracture characteristics by a CCS (constant cross-section) cutter. The results indicate that the increase in penetration (ranging from 2.5 mm to 5.5 mm) effectively increases chip masses between cuts and further promotes cutting efficiency. To further understand the fracture mechanism for various penetrations, 3D numerical simulations were performed using PFC 3D. The numerical fracture characteristics agree well with laboratory tests. In addition, the dynamic stress evolution analysis clearly shows that the increase in rolling force frequently results in stress concentrations in rock specimens. When stresses concentrate into critical values, fractures occur. Subsequently, these fracture propagations frequently result in stress dissipations and decreases in rolling force. Thus, the relation between the fluctuations of rolling force and the rock fractures is revealed. In addition, the increase in penetration results in the promoted stress concentrations. This phenomenon can explain why the increased penetration can result in severer fractures.

A Review of Hydromechanical Coupling Tests, Theoretical and Numerical Analyses in Rock Materials

“…[85] conducted true triaxial loading and unloading tests on coal samples and analyzed the deformation, seepage, damage, strength and damage characteristics of coal specimens. There are many similar experiments, and experimental studies on seepage-stress properties have been conducted by Liu et al[86], Yang et al[87], Wang et al[88], Liu et al[89], Chen et al[90], Du et al[91] and Zhao et al[92]. Further, in response to rocks' nonlinear hydromechanical coupling problem[93,94], some scholars have conducted test research, mainly studying the nonlinear characteristics of effective stress in rocks and the nonlinear behavior of seepage during rock deformation.…”