仿生镇压辊压实性能的有限元分析与试验验证

Finite Element Analysis and Experimental Verification of Compaction Performance of Biomimetically Polyhedral Press Roller

前期土槽试验结果表明,与传统镇压辊相比,采用Q235制成的正12面体仿生镇压辊的防壅土效果显著,但无法起到减粘降阻的效果。为此,采用有限元方法,从Mises应力云图、接触面积和位移云图3方面对比了正12面体仿生镇压辊和传统镇压辊的压实效果。结果表明:正12面体仿生镇压辊作用于土壤的Mises应力比传统镇压辊增加了40.07%,有利于种子与土壤紧密接触;正12面体仿生镇压辊与土壤的接触面积比传统镇压辊高3.10%,意味着正12面体仿生镇压辊起不到防粘的作用;正12面体仿生镇压辊对应土壤模型节点在X方向的位移比传统镇压辊降低5.88%,证实正12面体仿生镇压辊能起到一定的防壅土作用;两种镇压辊对土壤造成的Y方向的扰动范围及位移变化量相差不大,表明两种镇压辊压后土壤容重接近;正12面体仿生镇压辊造成土壤Z方向位移变化的最大值比传统镇压辊高出5.04%,意味着正12面体仿生镇压辊消耗的功要略高于传统镇压辊,与土槽试验结果吻合。研究结果可为农业机械触土部件压实性能的有限元分析提供数值模拟方法。

Previous soil bin test results showed that compared with conventional press roller,the biomimetically polyhedral press roller with regular dodecagon section made of Q235 showed the best performance of anti-hilling.However,it didn’t reduce soil adhesion and rolling resistance.In this paper,the compaction performance of biomimetically polyhedral press roller with regular dodecagon section was analyzed by finite element method,and compared with conventional press roller.Mises stress nephogram,contact area and displacement nephogram were adopted to compare the simulation results of two press rollers.Results showed that Mises stress between bionic press roller and soil was 40.07%higher than that of conventional press roller,which was beneficial to the close contact between seeds and soil.The contact area between bionic press roller and soil was 3.10%higher than that of conventional press roller,which means that the bionic press roller cannot prevent sticking.The displacement of node in X direction of the model was 5.88%lower than that of conventional press roller.It was proved that the bionic press roller can prevent hilling to some extent.The disturbance range and displacement variation of soil in Y direction after compaction by conventional press roller was similar to that of bionic press roller.It indicated that the soil bulk density of two press rollers were close.The maximum displacement in Z direction caused by bionic press roller was 5.04%higher than that of conventional press roller,which means the work consumption of the bionic press roller was slightly higher than that of conventional press roller.The results were in agreement with the soil bin test results.The results can provide a numerical simulation method for finite element analysis of compaction performance of agricultural machinery.