宁前胡仿生挖掘铲设计与试验

Design and Experiment of Ning-guo Radix peucedani Bionic Digging Shovel

针对宁前胡采挖过程中挖掘阻力大的问题,以鲨鱼背鳍为研究对象,并结合农艺要求,设计了一款宁前胡仿生挖掘铲;根据摩尔-库仑理论中土体应力分析,当选用鲨鱼背鳍结构作为仿生铲的凸起结构时,土壤更易达到破裂状态;通过三维扫描仪扫描鲨鱼标本,获取鲨鱼背鳍三维模型,根据背鳍三维模型确定仿生铲的凸起结构,并通过NX12.0创建仿生挖掘铲三维模型;利用三维扫描仪获得宁前胡根茎外形轮廓特征,创建宁前胡根茎的离散元模型,并选用Hertz-Mindlin with JKR建立宁前胡根茎-土壤离散元复合模型;通过离散元仿真对比试验,得出X、Y、Z方向颗粒位移和挖掘阻力的平均值,分析挖掘铲的减阻机理,仿生铲比平面铲在采挖过程中阻力减小14.37%;通过开展土槽试验,对比根茎挖掘效果,与仿真试验中得出的宁前胡根茎在仿生挖掘铲挖掘后,根茎在X、Y、Z方向上有更好的位移表现,仿生铲和平面铲的挖掘阻力平均值分别为1 342.28、1 622.73 N,仿生铲比平面铲在采挖过程中阻力减小17.28%,与仿真试验得出的减阻率十分接近,满足宁前胡采挖过程中的减阻要求。

To address the problem of high digging resistance during the excavation of Ning-guo Radix peucedani,a bionic digging shovel was designed with the shark dorsal fin as the research object;according to the soil stress analysis in Moore-Coulomb theory,the soil was more likely to reach the rupture state when the shark dorsal fin structure was selected as the raised structure of the bionic shovel.The shark specimen was scanned by 3D scanner,the shark dorsal fin 3D model was got,the projection structure of the bionic shovel was determined according to the dorsal fin 3D model,and the bionic digging shovel 3D model was created by NX12.0;the shape profile characteristics of the rootstock of Ning-guo Radix peucedani were obtained by 3D scanner,and the discrete element model of the rootstock of Ning-guo Radix peucedani was created,and the discrete element composite model of Ning-guo Radix peucedani rootstock-soil was established by Hertz-Mindlin with JKR;through the discrete element simulation comparison,the average values of particle displacement and excavation resistance in X,Y and Z directions were obtained from the simulation test,the drag reduction mechanism of excavating shovels was analyzed,and the resistance of the bionic shovel was reduced by 14.37%compared with the plane shovel in the excavation process;by conducting soil trench tests and comparing the rhizome excavation effect,it was basically consistent with the better displacement performance of Ning-guo Radix peucedani rhizome in X,Y and Z directions after excavation with the bionic digging shovel derived from simulation tests,and the average values of excavation resistance of the bionic shovel and the plane shovel were 1342.28N and 1622.73N,respectively.The resistance of the bionic shovel was 17.28%lower than that of the flat shovel in the excavation process,which was very close to that of the simulation test and met the requirements of resistance reduction in the excavation process of Ning-guo Radix peucedani.