Modelling and experimental investigation of cobalt - Rich crust cutting in ocean environment

Abstract

This paper focuses on modelling and experimental investigation of cobalt - rich crust cutting by deep sea mining vehicle in low confining pressure. The prediction accuracy of brittle material theoretical models was evaluated by the experimental cutting force obtained from the cobalt - rich crust cutting test. The results show that in 15 MPa confining pressure, the peak cutting force predicted by Evans model is closer to the experimental value when the compressive strength of cobalt - rich crust is less (Take cobalt - rich crust 1 strength as the standard). When the compressive strength of cobalt - rich crust exceeds cobalt - rich crust 1 and the cutting depth is larger, the predicted value of Roxborough model is more accurate. It is underestimated to the cutting forces acting on soft cobalt - rich crusts, semi-hard cobalt - rich crusts, hard cobalt - rich crusts and very hard cobalt - rich crusts by Evans model, which are about 85%, 76%, 91% and 74% respectively. The calibration factor is introduced to modify the peak cutting force estimated by Evans model. Finally, the modified cobalt - rich crust cutting mechanical model in ocean environment is obtained.