目的 深入研究果枝修剪过程特性及切割机理，为优化修剪机具核心剪切部件、提高电动修剪机切割性能提供参考。方法 以‘石硖’品种龙眼树枝为试验对象，采用ANSYS/LS-DYNA对树枝切割过程进行有限元仿真，搭建树枝切割试验平台进行切割试验，验证仿真模型的准确性，使用高速摄像机观察树枝切割过程，分析动刀片、树枝、定刀在切割过程中的应力分布及切割机理，确定最大等效应力出现的区域。结果 实际试验与仿真试验的切割过程都可分为5个阶段：挤压阶段、切入剪切阶段、稳定剪切阶段、剪断阶段、树枝振动阶段，实际切割力略大于仿真值，切割10、15和20 mm直径树枝刀具峰值切割力实际值与仿真值最大相对误差为7.8%，平均相对误差为7.0%，试验和仿真切割力曲线趋势大致相同。切割过程中动刀片、树枝和定刀最大等效应力出现在刀刃、树枝和定刀切口附近，动刀片、定刀最大等效应力均小于刀具材料屈服极限，刀具不会发生失效。结论 该有限元模型与实际情况基本符合，对修剪机具的设计和改进具有一定的参考价值。
Objective The goal was to in depth study the pruning process characteristics and cutting mechanism of fruit branches, and provide a reference for optimizing the core cutting components of pruning machines and improving the cutting performance of electric pruning machines.Method Taking the branch of ‘Shixia’variety of longan as the test object, ANSYS/LS-DYNA was used to perform finite element simulation of the branch cutting process. We built a branch cutting test platform for cutting experiments, verified the accuracy of the simulation model, used a high-speed camera to observe the branch cutting process, analyzed the stress distribution and cutting mechanism of moving blades, branches, and fixed blades in the cutting process, and determined the area where the maximum equivalent stress occured. Result The cutting process of actual test and simulation test could be divided into five stages including the extrusion stage, cutting-in shearing stage, stable shearing stage, shearing stage and branch vibration stage. The actual cutting force was slightly higher than the simulation value. The maximum relative error between the actual value and the simulation value of the peak cutting force of the cutter for cutting 10，15 and 20 mm diameter branches was 7.8%, and the average relative error was 7.0%. The trends of the experimental and simulated cutting force curves were roughly the same. During the cutting process, the maximum equivalent stresses of the moving blade, branch and fixed knife appeared near the cutting edge, branch and fixed knife cut. The maximum equivalent stresses of the moving blade and fixed knife were both less than the yield limits of the tool materials, and the tools would not fail.Conclusion The finite element model is basically consistent with the actual situation and has certain reference value for the design and improvement of pruning machine.