Experimental Research on the Bending and Fracture Characteristics of Cotton Stalk

2021 ◽  
Vol 64 (6) ◽  
pp. 1771-1779
Author(s):  
Peng Jiang ◽  
Yaping Li ◽  
Jiali Li ◽  
Hewei Meng ◽  
Xiangbin Peng ◽  
...  
Keyword(s):  
Moisture Content ◽  
Discrete Element Method ◽  
Fracture Energy ◽  
Block Design ◽  
Discrete Element ◽  
Cotton Stalk ◽  
Fracture Characteristics ◽  
The Relationship ◽  
Specific Fracture ◽  
Element Method

HighlightsA two-factor randomized block design was used to study the influence of experimental factors on indicators.Specific fracture energy can indicate the relationship between mass and power.A cotton stalk model was established using the discrete element method (DEM).Abstract. Effectively chopping of the mixture of mulch film and cotton stalk recycled by machine is the only way to achieve subsequent separation of the materials. Cotton stalk is one of the main components of the mixture. According to the working principle of a chopping device, the bending and fracture characteristics of cotton stalk samples were measured. A two-factor random block design was used to study the effects of moisture content and sample location on the plant on the mechanical characteristics of the stalk samples. According to the results, the specific fracture energy of the stalk samples was calculated. The results showed that the relationship between the moisture content and bending performance of the samples was an inverse proportional function in general. However, when the moisture content was 20% to 30%, the fracture energy in the double-support bending tests was low, which was therefore the most suitable condition for chopping. In addition, a cotton stalk model was established using the discrete element method (DEM), and the optimal parameter combination was determined. Compared with the actual test results, the model error of the peak bending force was 1.20%. This study can support the analysis of chopping device simulation and material preparation in experimental research. Keywords: Bending fracture characteristics, Cotton stalk, Discrete element method, Three-point bending test.

Failure Surface Variation Obtained with the Truss-Like Discrete Element Method

2015 ◽  
Vol 784 ◽  
pp. 225-232
Author(s):  
Guilherme Schumacher da Silva ◽  
Fabrício Goulart Fernandes ◽  
Angélica Bordin Colpo ◽  
Vicente B. Puglia ◽  
Luis E. Kosteski
Keyword(s):  
Spatial Distribution ◽  
Discrete Element Method ◽  
Fracture Energy ◽  
Failure Criterion ◽  
Failure Surface ◽  
Discrete Element ◽  
Constitutive Law ◽  
Surface Variation ◽  
Spatial Lattice ◽  
Element Method

This paper presents the study of failure surface obtained in the truss-like Discrete Element Method (DEM). The element constitutive law considers the fracture energy of the material and its spatial variation is used to take into account the heterogeneity of the simulated materials. It is studied the influence of spatial distribution of fracture energy and the spatial lattice perturbation on the DEM failure surface. A DEM failure criterion is compared with concrete and rock failure.

Experimental Study and Computer Simulation of Compression Characteristics and Crushing of Chinese Cabbage Seeds

2020 ◽  
Vol 36 (5) ◽  
pp. 815-825
Author(s):  
Shengsheng Wang ◽  
Jinpeng Hu ◽  
Jiangtao Ji ◽  
Hao Zhou ◽  
Jing Pang
Keyword(s):  
Moisture Content ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Physical Experiment ◽  
Distribution Law ◽  
Crushing Force ◽  
Mean Diameter ◽  
Cabbage Seed ◽  
1000 Grain Weight ◽  
Element Method

HighlightsBasic physical properties and mechanical parameters related to moisture content and compression orientation.A discrete model of cabbage seed was established by discrete element method.Crushing simulation has high consistency and small deviation compared with physical experiment.Abstract. To reduce the mechanical damage to cabbage seeds during combined harvesting, storage, and processing and to explore the mechanism of grain breakage, the basic physical parameters, such as the 1000-grain weight and the triaxial size under different moisture content (6.38%~15.30%), and the compressive mechanical properties under different loading methods (ventral loading and lateral loading) were studied. The discrete element method was used to establish a BPM model of cabbage seed. The distribution law underlying macroscopic cracks, evolutionary mechanism of internal damage and the micromechanical response during the compression of cabbage seeds were simulated. The results showed that the triaxial size, 1000-grain weight, arithmetic mean diameter and geometric mean diameter of cabbage seeds were related to the moisture content. The crushing force and apparent elastic modulus were related to the moisture content and the loading method. The distribution law of macroscopic cracks during the simulation processing was consistent with the physical experiment, and it was accompanied by increases in cracks and changes in the internal stress. In comparing the crushing force-displacement curves under the two compression modes, the law of curves between physical and virtual experiments was similar, and the peak values were very close, which indicated the feasibility of using the discrete element method to simulate the crushing of cabbage seeds during the compression process. Keywords: Cabbage seeds, Compression test, Cracks, DEM, Stress.

scholarly journals Optimal Speed Control for a Semi-Autogenous Mill Based on Discrete Element Method

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 233
Author(s):  
Xiaoli Wang ◽  
Jie Yi ◽  
Ziyu Zhou ◽  
Chunhua Yang
Keyword(s):  
Sliding Mode Control ◽  
Discrete Element Method ◽  
Rotation Speed ◽  
Sliding Mode ◽  
Discrete Element ◽  
Operating Parameters ◽  
Optimal Speed ◽  
Mode Control ◽  
The Relationship ◽  
Element Method

The rotation speed of a mill is an important factor related to its operation and grinding efficiency. Analysis and regulation of the optimal speed under different working conditions can effectively reduce energy loss, improve productivity, and extend the service life of the equipment. However, the relationship between the optimal speed and different operating parameters has not received much attention. In this study, the relationship between the optimal speed and particle size and number was investigated using discrete element method (DEM). An improved exponential approaching law sliding mode control method is proposed to track the optimal speed of the mill. Firstly, a simulation was carried out to investigate the relationship between the optimal speed and different operating parameters under cross-over testing. The model of the relationships between the optimal rotation speed and the size and number of particles was established based on the response surface method. An improved sliding mode control using exponential approaching law is proposed to track the optimal speed, and simulation results show it can improve the stability and speed of sliding mode control near the sliding surface.

Discrete element method to model cracking for two layer systems

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 101-108
Author(s):  
Daniel Varney ◽  
Douglas Bousfield
Keyword(s):  
Discrete Element Method ◽  
Flexural Modulus ◽  
Single Layer ◽  
Discrete Element ◽  
Flexural Stress ◽  
Layer System ◽  
Three Point Bending ◽  
Moving Force ◽  
Coating Layers ◽  
Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

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