| The cutterhead is one of the core components of the cutter suction dredger.During the construction of the cutter suction dredger,the cutterhead directly engages with the cutting medium and bears huge cutting load.At the same time,the cutterhead acts on the cutting medium with producing a large amount of debris and its working performance directly affects construction efficiency.Based on the above problems,obtaining the cutterhead’s dynamic cutting load and debris movement by analyzing the dynamic cutting process are of great significance to optimize cutterhead structure design,reduce power consumption,reduce wear and improve transmission efficiency.Therefore,based on the discrete element method,the numerical simulation of the cutting process was studied in this paper.Firstly,the models needed by the simulation were built,and the calibration method of microscopic parameters of discrete element contact model of rock materials was researched and corrected.The three-dimensional model of the cutterhead was established according to the experimental cutterhead.The material parameters and shape parameters of the discrete element particle model were determined respectively according to experimental materials and the shape parameters of debris.Then,the virtual friction angle test was used to calibrate the relevant friction coefficient.Both of the virtual uniaxial compression test and the virtual Brazilian test were used to calibrate the microscopic parameters of the bonding particle contact model,which were used to establish discrete element particle bed model that was able to reflect the macroscopic mechanical properties of experimental materials.In addition,the calibration process of the contact model microscopic parameters was corrected.It was found that the stiffness needed recalibration in uniaxial compression test,and the effect of loading mode,loading speed and time step to calibration result was researched.Secondly,the discrete element numerical simulation of the dynamic cutting process of cutterhead rock was carried out.The result showed that the generation and movement of the debris and the cutting morphology were consistent with the actual conditions.The loading condition of the cutterhead was consistent with the experimental and finite element simulation results basically,which verifies the feasibility and reliability of the simulation process.Meanwhile,the influence of cutting speed and rotation rate on the load condition of the cutterhead was studied,and that the speed has a great influence on the generation and movement of debris was found.In order to obtain greater debris transmission,the more appropriate rotation rate should be selected.In this paper,the calibration method of the microscopic parameters of the discrete element contact model of rock materials was studied and corrected,which provided a reference for the discrete element modeling method of rock materials.Meanwhile,the dynamic cutting process of cutterhead cutting rocks was simulated and analyzed,which provided means for load prediction of the cutterhead and the basis for the study of debris transmission. |
