杨望, 贾丰云, 杨坚. 木薯块根挖掘作业过程的数值模拟[J]. 工程力学, 2013, 30(6): 301-307. DOI: 10.6052/j.issn.1000-4750.2012.02.0100
引用本文: 杨望, 贾丰云, 杨坚. 木薯块根挖掘作业过程的数值模拟[J]. 工程力学, 2013, 30(6): 301-307. DOI: 10.6052/j.issn.1000-4750.2012.02.0100
YANG Wang, JIA Feng-yun, YANG Jian. NUMERICAL SIMULATION OF DIGGING PROCESSES OF CASSAVA ROOT[J]. Engineering Mechanics, 2013, 30(6): 301-307. DOI: 10.6052/j.issn.1000-4750.2012.02.0100
Citation: YANG Wang, JIA Feng-yun, YANG Jian. NUMERICAL SIMULATION OF DIGGING PROCESSES OF CASSAVA ROOT[J]. Engineering Mechanics, 2013, 30(6): 301-307. DOI: 10.6052/j.issn.1000-4750.2012.02.0100

木薯块根挖掘作业过程的数值模拟

NUMERICAL SIMULATION OF DIGGING PROCESSES OF CASSAVA ROOT

  • 摘要: 为了获得木薯块根挖掘铲作业时挖掘铲与土壤的作用过程、块根应力变化过程和挖掘铲各结构参数对作业质量的影响规律,该文采用ANSYS/LS-DYNA显式动力学仿真软件,利用拉格朗日算法和光滑粒子流体动力学(Smoothedparticlehydrodynamics,SPH)算法相结合的方法及修正的摩尔-库仑屈服准则,建立挖掘铲-茎秆-块根-土壤系统的动力学可视化仿真模型,对块根挖掘松土过程进行数值模拟分析,在微观层次上研究了挖掘铲的松土机理、土壤的变形、破裂、疏松过程和块根的应力变化过程,同时,采用单因素试验方法,研究了挖掘铲结构参数对牵引阻力、松土效果及块根有效应力的影响规律。结果表明:土壤被铲尖抬起,产生弯折、剪切破裂是挖掘作业土壤疏松的主要原因;在挖掘松土过程中,块根受土壤挤压产生弯曲变形。入土角和铲宽增大,牵引阻力增大,松土程度增加,但块根的弯曲变形也增大,有效应力增大,块根易产生折断,造成收获损失,而翼张角增大,牵引阻力减小,松土程度减小。

     

    Abstract: To analyze the interaction between the digging shovel and the soils,as well as the stress variation of the cassava roots and the influence of structural parameters of the digging shovel to the digging performance,a visual dynamic simulation model of the digging shovel-stem-root-soil system is established,which is based on the ANSYS/LS-DYNA explicit dynamic software,the Lagrangian algorithm,the Smoothed particle hydrodynamics (SPH) algorithm and the modified Mohr-Coulomb yield criterion.The digging process is numerically simulated with the proposed model and the loosening soil mechanism of the digging shovel,soils deformation,fragmentation and loosening,and stress variation of cassava roots are studied at micro level.In addition,the effects of shovel structural parameters on the traction resistance,the loosening soil,and the effective stress of cassava roots are investigated by using a factorial experiment with single factor.The results show that soils are bended and thus broken into fragments when they are uplifted by the digging shovel,which is the main reason for soil loosening.The extrusion caused by soils bending and deformation leads to the bending deformation of cassava roots during loosening soils.When the penetration angle and the width of digging shovel increase,the traction resistance will increase and the soils loosening is improved.But the bending deformation and the effective stress of cassava roots also increase,which may break the roots and thus result in loss in cassava yield.When the wingspan angle of digging shovel is enlarged,the traction resistance and the soil loosening will decrease.

     

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