绳索离散元模型构建方法与拉伸和弯曲过程力学分析

Discrete Element Modeling Method of Rope and Mechanical Analysis of Tensile and Bending Processes

摘要:

基于有限元（FEM）构建的绳索模型结构复杂，主要用于绳索结构力学分析，其准确性受绳索结构影响大，导致模型适应性不好。基于离散元（DEM）构建结构简单、适应性强的绳索模型仍是一个难题。提出了一种基于DEM的绳索建模及参数标定方法。构建的绳索模型为圆柱形，内部包含不同尺寸的三角壳体元件及其关节。三角壳体元件之间的力与弯矩分别以线弹性模型和双线性模型连接。通过拉伸和三点弯曲试验，分别以抗拉强度、弹性模量为响应值对绳索模型的离散元参数进行了标定。通过抗拉强度和弹性模量回归方程求解确定了绳索模型离散元参数最优组合。验证试验结果表明，绳索模型抗拉强度误差、弹性模量误差分别为2.32%、1.74%。拉伸、弯曲曲线平均误差分别为6.65%、7.35%。力学分析表明，DEM模型可用于分析绳索受力过程中的局部力学响应。构建的DEM基绳索模型为单股结构，与FEM基绳索模型相比，结构简单，具有普适性。

Abstract:

The rope model constructed based on the finite element method (FEM) has a complex structure and is mainly used for the mechanical analysis of rope structure, and its accuracy is greatly affected by the rope’s structure, resulting in poor model adaptability. The construction of structurally simple and adaptable rope models based on the discrete element method (DEM) is still a challenge. A rope modeling and parameter calibration method based on the DEM was proposed. The constructed rope model was cylindrical and contained triangular shell elements with different sizes and their joints. The forces and moments between the triangular shell elements were connected by a linear elastic model and a bilinear model, respectively. The DEM parameters of the rope model were calibrated by tensile and three-point bending tests with tensile strength and elastic modulus as response values, respectively. The optimal combination of the DEM parameters of the rope model was determined by solving the tensile strength and elastic modulus regression equations. The results of the validation tests showed that the tensile strength error and elastic modulus error of the rope model were 2.32% and 1.74%, respectively. The average errors of tensile and bending curves were 6.65% and 7.35%, respectively. Mechanical analyses showed that the DEM model can be used to analyze the local mechanical response of the rope during force application. The DEM-based rope model constructed was a single-strand structure. Compared with the FEM-based rope model, the structure was simple and universal.