Optimization Design and Experimental Analysis of Resistance-Reducing Anti-Fracture Rotary Blade Based on DEM Techniques

To address the significant cutting resistance and fracture susceptibility of rotary blades, an innovative blade design was conceived to minimize resistance and enhance fracture resistance. By analyzing the interaction between the blade, soil, and root systems, an optimized design for the blade structure’s breakage resistance was developed. The theory of eccentric circular side cutting edges was applied to redesign the curve of the side cutting edge, and kinematic analysis was conducted to determine the optimal edge angle (26.57°). A flexible body model of corn residues was established, and cutting resistance measurements indicated a 15.1% reduction in cutting resistance. The breakage resistance of the rotary blade was validated using a discrete element method–finite element method (DEM–FEM) coupling approach. The results demonstrated the following: neck stress (−16.85%), specific strength efficiency (+9.72%), specific stiffness efficiency (+9.78%), fatigue life (+39.08%), and ultimate fracture stress (+20.16%), thereby meeting the design objectives. The comparison between field trial results and simulation data showed an error rate (<5%), confirming the simulation test’s feasibility. These findings provide theoretical references for reducing cutting resistance and enhancing breakage resistance in rotary blades.