Numerical Simulation Of Shear Strength Of Ice And Water Mixtures Based On Coupled DEM-LBM Solution Strategy

Ice and water mixtures are prevalent in polar crushed ice channels and in the keel of ice ridges,in order to investigate the shear properties of ice and water mixtures,a combination of model tests and numerical simulations is used.The model tests use polypropylene spheres to simulate real crushed ice,and laboratory punch through tests are carried out to investigate the shear strength of unconsolidated crushed ice,while the numerical simulations use a coupled lattice boltzmann method(LBM)and discrete element method(DEM)solution strategy to simulate the model punch through tests.The coupled DEM-LBM algorithm is developed for the interaction between circular cells and fluid,in which the fluid is modelled using the lattice boltzmann method,the interaction between solid particles is solved using the discrete element method,and the particle motion boundary is treated using the immersed moving boundary method(IMB).The developed coupling algorithm is used to simulate the settling motion of different numbers of spheres in a fluid.The effect of wall surface on sphere settling,the effect of lattice size on the accuracy of the simulation,and the DKT phenomenon(drafting,kissing and tumbling)during the settling of double spheres and the phenomenon of multi-spheres settling were well reproduced.The accuracy of the algorithm was verified.The study of the shear properties of ice and water mixtures focuses on the shear strength of unconsolidated crushed ice,and is carried out using a combination of model tests and numerical simulations.In the model tests,a test rig was constructed and polypropylene spheres were used to simulate real crushed ice.The effects of loading rate and mixture thickness on the punch through test were investigated.The results show that the peak value of loading resistance of ice water mixture increases with the increase of loading rate and thickness,which is linear with loading rate in punch through test.The shear strength of crushed ice has a positive correlation with the loading rate and a negative correlation with the stacking thickness as calculated by the available equations.The model test was numerically simulated using the coupled DEM-LBM algorithm and compared with the model test results,and the simulation results were good.The effects of crushed ice size,water tank size and porosity of ice and water mixtures on the punch through test were investigated.The results show that the size of the flume length has little effect on the test,but the size of the crushed ice and porosity of ice and water mixtures directly affect the shear strength of the mixture.In addition,it usually used the hydrodynamic loads obtained in hydrodynamic tests to replace the hydrodynamic loads at the peak of the resistance of the compression shear test,which is no longer applicable in-high speed punch through tests,so it is necessary to apply numerical simulations to assist in the study of model compression shear tests.