Abstract Accurate predictions of the mechanical response of root-soil systems are required for assessing and reducing the risk of landslides, surface erosions, and lodging. The present paper proposes the use of the node-to-segment (NTS) approach with the finite element method for predicting contact phenomena between roots and soils, such as collision, sliding, and separation. To obtain reliable predictions for the deformation of such geometrically complex problems, a stabilizing algorithm within the NTS approach is proposed and implemented here. The proposed algorithm prevents the well-known non-uniqueness problem of the pairing algorithm in the NTS approach, which has been an obstacle to applying the approach to root-soil systems. The current method is employed for two numerical examples. The first is an example of validation, in which pullout experiments are re-analyzed to examine the applicability of the method to a geometrically simple root-soil contact problem. It is shown that the current method provides a reasonable prediction of the pullout response, and that both the friction and the cohesion can also be accurately estimated with it. The second is an example of a realistic problem, in which a 2-D lodging experiment, analogous to pile-loading problems, is conducted and simulated to demonstrate the accuracy and applicability of the NTS approach in plant-scale problems with complex root geometries. The relationship between the displacement and the reaction force of the simulation is consistent with that of the experiment, and it enables the visualization of the stress contour and deformation of the rhizosphere.

中文翻译：

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基于节点到段方法的二维根-土接触问题的实验和有限元分析

摘要 为了评估和降低滑坡、地表侵蚀和倒伏的风险，需要准确预测根-土系统的机械响应。本文提出使用节点到段 (NTS) 方法和有限元方法来预测根和土壤之间的接触现象，例如碰撞、滑动和分离。为了获得对此类几何复杂问题的变形的可靠预测，本文提出并实施了 NTS 方法中的稳定算法。所提出的算法防止了NTS方法中众所周知的配对算法的非唯一性问题，这一直是将该方法应用于根土系统的障碍。当前方法用于两个数值示例。第一个是验证的例子，其中重新分析拔出实验以检查该方法对几何简单的根 - 土壤接触问题的适用性。结果表明，当前的方法提供了对拉拔响应的合理预测，并且摩擦力和内聚力也可以用它来准确估计。第二个是一个现实问题的例子，其中进行和模拟类似于桩加载问题的二维倒伏实验，以证明 NTS 方法在具有复杂根几何结构的植物规模问题中的准确性和适用性。模拟的位移与反作用力的关系与实验一致，可以实现根际应力等高线和变形的可视化。