Bending mechanics test and parameters calibration of ramie stalks

Abstract

Research and development of ramie harvesting equipment is a key link to revitalize ramie industry, problems such as the tendency of stalks to tangle and clog the machine are very problematic, seriously affect the quality and fluency of the harvester. The structure of ramie stalk is complex, and the mechanical properties of each component vary greatly, collision between stalk and machine creates complex stress relationship. By building a finite element model, it is possible to analyze the stress state of the stalk during bending from a microscopic perspective, and to analyze the complex stress–strain situation within the stalk. The purpose of this paper is to establish a standard ramie stalk bending finite element model to provide a theoretical basis for the subsequent kinematics and dynamics. Firstly, material experiments were carried out on ramie straw. The structural and mechanical parameters of the straw components were obtained through measurement and calculation tests, and the force–deformation curves for straw bending were obtained. Bending finite element simulations were carried out on the basis of mechanical tests, and the parameters such as dynamic friction coefficient, wood Poisson's ratio and bast Poisson's ratio were determined by the central combination design. Then established an accurate bending finite element simulation model of ramie stalk, the accuracy of the model was verified at the end. In this paper, the key parameters of the ramie stalk model were calibrated through a combination of material tests and simulations. All parameters of the ramie stalk model were finally obtained, and the bending mechanical properties of the ramie stalk were analysed by applying finite element analysis. This bending mechanics simulation model can be used for kinematic and dynamics simulation analysis of conveying and baling to provide a theoretical basis for the structural design of the harvester. The methods explored here can be applied to other slender straw crops.

Quantitative assessment and optimization of parallel contact model for flexible paddy straw: a definitive screening and central composite design approach using discrete element method

“…Maximum and minimum bending force and shear force were varied from 2.3 to 8.9 N and 101.8 to 143 N 35 . The relative error between the actual and simulated model is less than 10 per cent under the acceptable limit and represents the real behaviour of straw 12 .…”

“…The processes of cutting rattan straw and maize straw scarfskin, respectively, to get insights into straw-cutting behaviour 10 , 11 . Creating a standard ramie stalk bending model through material experiments and finite element method simulations provides a vital foundation for designing efficient harvesting equipment 12 . Analytical model (AM) with the Discrete Element Method (DEM), highlighting DEM’s superior performance in predicting cutting forces and soil profile changes 13 .…”

Finite Element Simulation Parameter Calibration and Verification for Stem Cutting of Hydroponic Chinese Kale

“…Huang et al [20] used a three-point bending simulation and test to calibrate the anisotropic Poisson's ratio of phloem and the isotropic Poisson's ratio of xylem for industrial hemp stems. Si et al [21] calibrated the rolling friction coefficient, the Poisson's ratio of phloem, and the Poisson's ratio of xylem for ramie stems using a three-point bending simulation and test. The above studies show that the calibration of the mechanical characteristic parameters related to crop stem cutting using the finite element simulation method possesses high accuracy.…”

Design and Parameter Optimization of Conveying and Baling Devices for Ramie Cutting and Baling Machine

“…Combined with the physical characteristics of ramie stalks and the technical requirements of harvesting, this paper designs a hand-held ramie cutting and baling machine with a tracked chassis that is flexible, simple to operate and easy to maintain [19]. It can complete the ramie cutting, conveying and baling functions in one go.…”