基于SPH-FEM耦合的残膜-根茬-弹齿互作规律研究

Residual Film-Root Stubble-elastic Tooth Interactions Based on SPH-FEM Coupling

摘要:

针对新疆棉田现有的残膜回收技术主要侧重于机械性能，忽略收膜过程中根茬对残膜的拖拽作用，导致残膜容易挂在根茬上的问题，本文通过对捡拾弹齿在含有根茬回收残膜时理论及仿真分析，确定了弹齿工作参数。使用有限元法（FEM）与光滑粒子流体动力学（SPH）相耦合算法，将弹齿、根茬、残膜构建为FEM网格，土壤构建为SPH颗粒，对残膜所受到的剪切应变、峰值应力、拾取高度及受到根茬的拉扯应力进行模拟。模拟含有棉秆根茬时的残膜回收情况，分析回收效果。田间试验结果表明，当根茬高度为5~9cm时，残膜平均回收率为91.25%，根茬上残膜残留率为4.30%。当根茬高度为10~12cm时，残膜平均回收率为82.66%，根茬上残膜残留率为12.55%。根茬高度为5~9cm的地块比根茬高度为10~12cm的地块回收率提高8.59个百分点，根茬上的残膜残留率降低8.25个百分点。根茬高度5~9cm的地块中，根茬上残膜残留量占未回收残膜总量比根茬高10~12cm地块低45.34%。研究结果为根茬与残膜相关性以及残膜回收率提升提供了理论支持。

Abstract:

The existing residual plastic film recovery techniques in Xinjiang’s cotton fields primarily focus on mechanical properties, neglecting the dragging effect of root stubble on the film during collection. This results in residual film readily becoming entangled in the root stubble. It confirmed the operational parameters of the pick-up teeth by analyzing the recovery of residual film when picking up teeth in conditions containing root stubble. Employing a coupled finite element method (FEM) and smooth particle hydrodynamics (SPH) algorithm, the tines, stubble, and residual film were modeled as FEM meshes, while the soil was represented as SPH particles. This enabled simulation of the shear strain, peak stress, pick-up height, and tensile stress exerted by root stubble on the residual film. The recovery of residual plastic film in the presence of cotton root stubble was simulated and the recovery efficiency was analyzed. Field trial results indicated that when root stubble height ranged from 5cm to 9cm, the average recovery rate of residual film reached 91.25%, with a residual film retention rate on root stubble of 4.30%. When root stubble height was 10~12cm, the average residual film recovery rate across plots was 82.66%, with 12.55% of residual film remaining on the root stubble. Plots with root stubble heights of 5~9cm exhibited an 8.59 percentage point increase in recovery rates compared with plots with root stubble heights of 10~12cm, alongside an 8.25 percentage point reduction in residual plastic film on stubble. In trial plots with root stubble heights of 5~9cm, the residual film retention rate on root stubble was 45.34% lower than in plots with root stubble heights of 10~12cm. The research findings can provide theoretical support for the correlation between root stubble and plastic film remnants, as well as for enhancing the recovery rate of plastic film remnants.