藜麦秸秆接触物理参数测定与离散元仿真标定

Determination of Quinoa Straw Contact Parameters and Calibration of Discrete Element Method Simulation

探明藜麦秸秆的力学特性是进行藜麦相关机械研发与优化的前提。以藜麦秸秆为研究对象,借助离散元建模软件(Discrete Element Method,DEM)对藜麦秸秆进行离散元建模,并通过物理试验与虚拟试验相结合的方法对藜麦的粘结接触模型(Bonded Particle Model,BPM)进行了参数校核。结果表明:(1)以300 mm/min为加载速度,对含水率为59.61%的陇藜一号藜麦秸秆进行径向压缩试验时,最大临界载荷为173.67 N,抗压强度为0.116 MPa;(2)对bond粘结模型进行参数校核后,得到单位面积法向刚度、单位面积切向刚度、临界法向应力临界切向应力及粘结半径分别为2e+09 N/m~3, 1.5e+09 N/m~3, 3e+07 Pa, 2e+07 Pa, 0.96 mm,此时离散元模型力学特性与藜麦秸秆相接近;(3)经过计算得到藜麦秸秆模型的抗压强度为0.120 MPa,与试验结果的相对误差为6.0%。试验结果验证了此参数组的准确性,也为藜麦秸秆的其他仿真试验提供参考。

Proving the mechanical properties of quinoa straw is a prerequisite for research and development and optimization of quinoarelated machinery. This paper takes quinoa straw as the research object and uses discrete element modeling software to conduct discrete element modeling of quinoa straw. In addition, parameters of the bonded particle model of quinoa were checked by combining physical test and virtual test. The results showed that the maximum critical load and compressive strength of quinoa straw with 59.61% water content were 173.67 N and 0.116 MPa when the radial compression test was carried out at the loading speed of 300 mm/min. After checking the parameters of bond model, the normal stiffness per unit area, tangential stiffness per unit area, critical tangential stress and bond radius were 2e+09 N/m~3, 1.5e+09 N/m~3, 3e+07 Pa, 2e+07 Pa and 0.96 mm respectively. After calculation, the compressive strength of the straw model was 0.120 MPa, and the relative error was 6.0%. The test results prove the accuracy of this parameter group,and also provide reference for other simulation tests of quinoa straw.