Numerical simulation study on wear failure of helical blade in coal seam with dirt band

In terms of the spiral drum of new MG400 / 951-WD shearer,the 3D entity models were established for the spiral drum and coal rock with dirt band using the Pro / Engineer. Then the coupling model was imported into ANSYS software for pre-processing. Material properties such as density,elastic modulus,Poisson’s ratio,com-pressive strength and tensile strength of the tooth tip alloy head,the matrix,the hub and the helical blade were set respectively. The physical and mechanical properties such as density,elastic modulus,Poisson’s ratio,cohesion,internal friction angle, tensile strength and Protodyakonov’s coefficient of coal and dirt sand were measured by experiments on the coal seam with dirt band in the Yangcun coal mine,so as to set the material properties of coupling models. Constitutive models of the coal rock with dirt band and the helical blade were defined as 096_BRITTLE_DAMAGE and 003_PLASTIC_KI- NEMATIC,respectively. The interception of coal particles and the wear of the helical blade were characterized through defining the failure of the coal rock with dirt band and the helical blade with ADD_EROSION. Based on the actual working conditions,the initial movement state of the shearer was defined at a 8 m / min of shearer advanced speed and a 60 r / min of shearer drum rotation speed. The output of the solution was set with DATABASE_RCFORC,and the final K file was imported into LS-DYNA / SOLVER for a solution. The wear domain,the stress nephogram,the working load spectrum and total wear volume of the helical blade were obtained through exhibiting the dynamics simulation for a so- lution,showing that the wear of the helical blade was found at the tail end and the outer edge of the blade. The most severe wear was at the tail end of the blade,being consistent with the wear of the blade in the actual condition. It’ s because a furrow wear land would be caused by wear debris falling off due to large friction resulted from the coal pile stacking at the tail end of the blade being pushed by the blade. Moreover,nonlinear impact loads generated in the cut- ting process of the helical drum would lead to large vibration,which brought about the outer edge of the blade at the lower end of the tooth holder being contact with the coal rock with dirt band,forming additional wears. Variation trends of the wear volume of the helical blade were obtained with Matlab after extracting the wear volume of the helical blade at different times,which found that the wear of the helical blade was increased with the working time,while the wear rate decreased with the working time. It’s caused by constant changes in the microscopic profile of the wear surface, which was consistent with the expanding wear domain at different times. The wear track of the helical blade was matched with Matlab to obtain the wear track equation of the helical blade.