固沙装备插草圆盘前进速度与阻力关系分析

Analysis on the relationship between the blade velocity and resistanceof the sand fixing equipment

关键词:  固沙插草  插草圆盘  草方格  离散元法

Key words:  inserting straws  disk blade  straw checkerboards  Discrete Element Method (DEM)

摘要:

针对机械化铺设草方格过程中纵向插草关键部件插草圆盘在竖直方向的插草阻力及其影响因素的问题，本文首先对草秆的运动规律进行了理论分析,得到了单根草秆被下压的时间和相邻两根草秆开始运动的时间差；然后计算得到了圆盘在一个运动周期内所接触的草秆数量，以及草秆在竖直方向的平动速度与圆盘前进速度的定量关系式。此外，我们搭建了用于插草的试验台以及土槽，采用竖直插草试验来标定草秆转动的角速度与角加速度。在此基础上，利用离散元法建立插草圆盘插草的草秆-沙土三维模型，利用离散元法仿真再现了插草圆盘插草过程中草秆的运动形态。研究结果表明：1）对草秆运动的理论分析结果适用于离散元仿真插草动态过程；2）圆盘在前进速度4-10cm/s的区间内所受竖直方向的稳态插草阻力几乎不受其影响；3）圆盘竖直方向插草阻力随着草秆铺设密度的增加而增大。

Abstract:

In order to study vertical inserting resistance of a disk blade and its influencing factors in the vertical direction of key inserts of longitudinally inserted grass in mechanized laying of grass squares, the straw movement rules were analyzed theoretically and the equations of the inserting time of a single straw downwards and the time duration of two adjacent straw starting to move were proposed. Then we calculated the number of straws contacting with the disk blade in each motion cycle and acquired the relationship between the translational vertical velocity of a straw and the forward speed of the blade. Besides, we established the experimental system for inserting straws and calibrated the angular velocity and the angular acceleration of side-straw-segments with the experiments. On the basis of the straw movement analysis, the three-dimensional numerical model of straw-sand was established with DEM, and the movement of straws was simulated in the inserting process of the blade. The result shows as follows: (1) the theoretical analysis results of grass stalk movement are applicable to the discrete-element simulation of the dynamic process of inserting grass; (2) the vertical steady state resistance of inserting straw is unaffected by the speed of blade in the interval from 4cm/s to 10 cm/s; (3) the resistance of the vertical direction of the disk increases with the increase of the grass stalk laying density.