Study of the effect of penetration depth and disc speed on cutting forces using LS-DYNA simulations

The forces applied to cutting discs are among the most important design parameters for tunnel boring machines (TBMs) used in rock excavation. These forces include normal and rolling forces, which are influenced by factors such as penetration depth, spacing, linear and rotational speed of the disc. Therefore, it is necessary to carefully examine these forces for the design of TBMs. Linear cutting tests are time-consuming and expensive, so high-accuracy numerical simulations can be a suitable alternative. In this article, LS-DYNA software was used to conduct simulations for the validation of two behavioral models of concrete, Johnson Halmquist (JHC) and RHT. The effect of variables such as penetration depth, linear and rotational speed of the disc on the forces was investigated. The results indicate that penetration depth has a significant effect on both normal and rolling forces. Increasing the penetration depth from 2.5 to 7.6 mm results in an increase in normal force from 96 to 159 kN and an increase in rolling force from 6.1 to 22.5 kN. As the linear and rotational speed of the discs increase, the forces decrease slightly. However, increasing the linear speed from 0.33 to 1.65 mm only causes a 13% decrease in normal force (from 155 to 175 kN) and a 5% decrease in rolling force (from 20.6 to 19.5 kN), according to the obtained results.