A numerical approach for modelling the ploughing process in sands

Ploughing processes are difficult to simulate using conventional approaches due to the occurrence of extremely large, predominantly plastic deformation. Numerical techniques such as the Material Point Method and the Discrete Element Method are, in principle, capable of reproducing the deformation observed in these evolutionary processes, but they are not without drawbacks, the most significant being the large processing times required. This paper presents a new numerical technique for modeling the ploughing process in sands. The method rests on the assumption that deformation occurs in the formof strong discontinuities, or shear bands, and considers the full process as a sequence of incipient collapse problems.Within an increment of deformation, the collapse mechanism furnishing the least resistance is used to update the deformed configuration and evaluate force. The model incorporates the effect of softening within the shear bands, as well as material avalanching observed as the slope of the free surface reaches the critical angle at which instabilities occur. Theoretical predictions are compared to experiments, and the basic similarities and difference are discussed.