Research On The Variable Curvature Law Of Directrix And Drag Reduction Of Bionic Bulldozing Plates

The energy loss and work efficiency of construction machinery and agricultural machinery are directly related to the contact surface of working parts,and the contact surface characteristics of working parts are affected by the collinear form of the surface.In order to optimize the shape of the contact surface,improve the design level of the surface,reduce the working resistance and energy consumption of construction machinery and agricultural machinery,the bulldozers with different alignment forms are further studied in this paper.Based on the previous research and analysis of single bionic claw toe,the complex curvature characteristics of the inner contour curve of vole's claw toe are the basic reason for the excellent drag-free and adhesion-reducing performance of vole's claw toe,which provides the basis for bionic research on the optimization of geometry and mechanical properties of bulldozer plate.In this paper,the data point coordinates of the inner contour curves of nine claw toes of voles are collected,and the coordinates of the corresponding points of the inner contour curves of nine claw toes are obtained.Then,the quadratic polynomial fitting equation is obtained by least square method,and the inverse equation of curvature and curvature mean of the inner contour curves of the fitting claw toes is obtained.Based on statistical eigenvalues,the law of variable curvature is analyzed.Using Solid Works three-dimensional mapping software,nine paw-toe fitting curve equation,curvature mean inverse equation and soil plate-soil cutting model with curve mean equation in line were established respectively.In order to increase the comparability of experimental analysis,four kinds of bulldozer-soil cutting models with cutting angles of 50 degrees,cycloid,involute and parabolic,are established.The model is imported into ANSYS/LS-DYNA to solve the problem.The operation results are further analyzed by the post-processor LS-PREPOST.The results show that the resistance of bionic bulldozers with good digging ability is lower than that of non-bionic bulldozers.Among the fourteen bulldozers,bionic bulldozers G has the lowest resistance and the best stress fluctuation,followed by parabolic and involute bulldozers,and cycloid and arc bulldozers have the greatest resistance and the worst stress fluctuation.The bulldozers were fabricated by using arc,cycloid,involute,parabola and the best bionic paw-toe fitting curve as the alignment line,and were tested in the laboratory soil trough.The test results show that the alignment form is an important factor affecting the working resistance of bulldozers.The drag reduction effect and mechanical properties of bionic bulldozers are the best,followed by parabolic and involute bulldozers,cycloidal and arc bulldozers,and the results of soil trough test and finite element analysis are the same.The above results show that the mechanical properties of bulldozers with extremum points in the quasi-linear curvature curve are excellent.The reason is that the bulldozers produce stress fluctuations in the soil ahead of them during the working process,which reduces the friction and fragmentation difficulty of the soil.