DEM Simulation In Wear Behaviors Of Bionic Structures Based On Four Wear-resistant Biological Surface Morphologies

This work firstly analyzed the wear-resistant properties of biological non-smoothmorphologies of Arca subcrenala Lischke, Arca inflata Reeve and Ostrich foot body surfacesby experiments. The mechanical model for bionic structures (prismatic, frustum, sphericaland stripy) are modeled based on the Discrete Element Method (DEM) theory. The DEMsimulation models and abrasive are modeled in PFC2D. The wear morphologies of thebionic structures were simulated using the two-dimensional abrasive wear simulation model.Through analysis on contact-bond, contact-force chains, velocity and displacement fields,the wear behaviors of inhomogeneous evolution process of the bionic structures are observed.In addition, the wear loss and wear resistance of the bionic structures were tracked and thewear resistant mechanism were further revealed. The results shows that the vertical cornersof bionic prismatic structure tends to be wear off; the bionic frustum structure demonstratessuperior function of wear reduction by allowing the abrasive to flow along the direction ofthe frustum shape; the bionic spherical structure shows predominant wear resistant propertybecause it disperses the abrasive motion; The stripy element can also significantly reduce theintensity when abrasive interacting with outside structure. From the analysis of the wearbehaviors, it indicates less loss of bionic cells can make great effect on protecting the loss ofwhole structure.Based on the simulation results in uniform scale, it indicates that the abrasive wear onlyhas minor mechanical effect on the matrix of bionic structures. Therefore the calculationamount for abrasive wear simulation can be reduced by using the hierarchical model or themulti-scale numeration. For this reason, the small elements in upper matrix area of the bionicstructures were substituted with big elements to reduce the calculation amount. The couplearea of the hierarchical model in bionic structure was achieved by adding suitable elementsand contact-bond. The hierarchical model for the abrasive system was accomplished usingradius expanding. The simulation results with hierarchical model saved the calculation timeand are demonstrated effectively on the comparing wear morphologies, contact-bond, wearloss and wear resistance with that of uniform model. In terms of the multi-scale abrasivesystem, both two dimensional and three dimensional multi-scale model of bionic prismaticstructure are built by using the Adaptive Continuum/DisContinuum Logic respectively inPFC2D and PFC3D. Last, the scheme for the multi-scale abrasive wear simulation isproposed. The multi-scale simulation for abrasive wear is of great importance to the researchof wear parts. To achieve the best wear properties of bionic structures subjected to different abrasiveradius, three levels of distance between bionic cells for each bionic structure are designedand their abrasive wear properties are simulated using the hierarchical model in PFC2D. Theresults show that when the distance between bionic cells become longer, the bionic prismaticstructure will be damaged as the crack at couple area extends during long time wearing.When both the cell distance and abrasive radius are in their highest level, greater fracturesoccurs on the vertical corners. Secondly, the simulation results demonstrate these four bionicstructures (prismatic, frustum, spherical and stripy) shows better wear resistant properties onthe condition that the distance between bionic cells is less than the width of bionic cell.However, the frustum structures always appear high wear resistant properties under givenconditions in this simulation. Moreover, the simulation results illustrate that the wear loss ofthe prismatic, frustum and spherical bionic structures increases when the radius of abrasiveparticles become bigger in the range of0.055-0.075mm. In addition, this work concludesthat the dynamic forces in X and Y direction increases respectively as the distance of bioniccells is widened. The numerical results provide fundamental references to the research ofabrasive wear parts in engineering, and a kind of board used for ball mill was designed andits work status was simulated by using PFC3D based on the optimization results. Meanwhile,a new simulation method for the wear properties study and optimization of wear parts isproposed.