Digging characteristics of grab based on DEM-MBD simulation and experiment

The grab bucket plays an important role in the construction process of dredging, and analyzing the excavation characteristics of the grab is helpful for the mechanical design of the grab bucket. In this investigation, the digging device and the digging mudstone are detailed as a system dynamic process, and a theoretical model for calculating digging resistance is established based on the Rankine theory. Furthermore, the particle shear test is performed to analyze the influence of changes in sand physical parameters on its shear characteristics. The DEM-MBD coupling simulation is adopted to calculate the particle distribution and the digging trajectory, and the influence of digging depth and particle cohesion strength is analyzed on the digging resistance. Moreover, an excavator digging experimental platform is established to validate the feasibility of the experimental results. The results show that the 10% moisture content is the inflection point of the sand particles physical and mechanical properties, and its shear strength decreases with the augment of moisture content; the variation law of the simulation results is consistent with the theoretical calculation, and the digging resistance reduction is proportional to the cohesion strength when the particles are completely sheared; the same key point parameter error of the digging curve obtained by the test and the simulation are consistent.