Promoted cutting and energy transition efficiency by an asymmetric cutter

Laboratory and numerical tests were performed to understand the rock breakage mechanism of a CCS (constant cross section) cutter and an asymmetric cutter. The laboratory and numerical tests consistently show that the asymmetric cutter frequently generates larger breakage areas and consumes less indentation energy than the CCS cutter, but there is a defect spacing of 70 mm. Thus, the asymmetric cutter frequently has a higher cutting efficiency than the CCS cutter. In addition, the numerical tests reveal that the CCS cutter first generates a plastic zone and subsequently forms cracks to connect with the defect tips. In this process, a large proportion of the energy is wasted in the particle friction in the plastic zone. However, the asymmetric cutter tends to form much smaller plastic zones, which makes it difficult to generate particle friction. Only a small amount of friction energy is consumed in the later crack propagation process. Thus, the asymmetric cutter has a higher energy transition efficiency than the CCS cutter.