Parameter Measurement and Calibration in Discrete Element Simulation of Broken Sweet Potato Seedlings

Guizhi Mu,Xieteng Qi,Wangzhi Zhang,Tingting Zhang,Shuwen Wang,Zhaoqin Lv

doi:10.3844/ajbbsp.2021.256.266

Abstract

Given the lack of accurate parameter values in discrete element simulation of sweet potato seedling mechanized recovery, a direct measurement and virtual calibration method was used to study the Discrete Element Method (DEM) simulation parameters of broken sweet potato stems and leaves. The intrinsic parameters, collision recovery coefficient and static friction coefficient of broken seedlings were acquired by physical experiments. Different parameter combinations were designed for DEM simulation. The intrinsic parameters of sweet potato leaves and other unmeasurable DEM simulation parameters were determined by stacking angle optimization simulation. Plackett-Burman test shows that the static friction coefficients of stem-stem and stem-steel and the rolling friction coefficients of stem-stem and stem-leaf all significantly influence the accumulation angle. The parameters that significantly influence the stacking angle of broken seedlings were sent to steepest ascent test and Box-Behnken test. The average stacking angle of 40.51° and the relative error of 0.972% indicate it feasible to calibrate DEM parameters by physical test and optimization simulation and the calibrated parameters can be used in DEM simulation of broken sweet potato stems and leaves.

Highlights

Sweet potato vines are excellent fresh feeds and silage and their mechanized recycling has economic and social benefits (Kakahy et al, 2014; Zhao and Gao, 2012; Guizhi et al, 2019)
Research on the action mechanism of sweet potato vines and harvesting machinery based on the Discrete Element Method (DEM) provides a theoretical basis for machinery design and optimization
The simulation data were compared with the physical test data, which provides a reference for the measurement and calibration of discrete element simulation parameters of sweet potato seedlings

Summary

Introduction

Sweet potato vines are excellent fresh feeds and silage and their mechanized recycling has economic and social benefits (Kakahy et al, 2014; Zhao and Gao, 2012; Guizhi et al, 2019). DEM simulation requires many parameters, including intrinsic parameters (e.g., density, shear modulus and Poisson's ratio of sweet potato seedlings) and contact parameters (e.g., collision recovery coefficients, rolling friction coefficients and static friction coefficients between seedling particles and between particles and machine) (Boac et al, 2009; Ucgul et al, 2014; Leblicq et al, 2016). How to determine these parameters is the premise of applying DEM to the research on mechanized recovery of sweet potato vines. The simulation data were compared with the physical test data, which provides a reference for the measurement and calibration of discrete element simulation parameters of sweet potato seedlings

Materials and Methods

Findings

Conclusion