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.

scholarly journals PARAMETER OPTIMIZATION AND EXPERIMENT OF SLIDER-HOLE-WHEEL SEED-METERING DEVICE BASED ON DISCRETE ELEMENT METHOD

2021 ◽  
pp. 410-420
Author(s):  
Xiaoshuang Zhang ◽  
Dequan Zhu ◽  
Kang Xue ◽  
Lanlan Li ◽  
Jianjun Zhu ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Hybrid Rice ◽  
Rotation Speed ◽  
Field Tests ◽  
Discrete Element ◽  
Seeding Rate ◽  
Simulation Experiments ◽  
Rice Seeds ◽  
Seed Metering Device ◽  
Element Method

To improve the adaptability and precision of the slider-hole-wheel seed-metering device to meet the requirements of precision sowing, the single factor simulation experiments and the three factors three levels of orthogonal simulation experiments were carried out based on the discrete element method. The rotation speed of the seeding shaft, the shape of the hole, and the depth of the hole were set as experiment factors. The results of simulation experiments showed that the qualified rate was the highest when the rotation speed of the seeding shaft was 30 r/min, the shape of the hole was oval, and the depth of the hole was 9 mm. The qualified rate, replay rate, and miss-seeding rate were 89.09 %, 3.64 %, and 7.27 %，respectively. The hybrid rice seeds of Zhongnong 2008, Chuangliangyou 4418, and Gangyou 898 were chosen as the materials for the bench and field seeding performance tests to verify the reliability of the simulation results. The test results showed that the qualified rate of Zhongnong 2008, Chuangliangyou 4418, and Gangyou 898 seed in bench tests were 85.07 %, 85.20 %, and 82.13 %, and the qualified rate of Zhongnong 2008, Chuangliangyou 4418, and Gangyou 898 seed in field tests were 82.13 %, 82.27 %, and 80.53 %. The seeding performance with the three kinds of rice seeds could meet the agronomic requirements for precision sowing of hybrid rice. The paper provided the basis for the structure optimization and seeding performance improvement of the slider-hole-wheel seed-metering device.

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.

Comprehensive performance analysis of a shearer drum in a complicated seam based on discrete element method

2021 ◽  
pp. 095440622110263
Author(s):  
Lijuan Zhao ◽  
Meichen Zhang ◽  
Baisheng Shi ◽  
Xionghao Liu ◽  
Yadong Wang
Keyword(s):  
Discrete Element Method ◽  
Loading Rate ◽  
Rotation Speed ◽  
Discrete Element ◽  
Design Parameters ◽  
Main Function ◽  
Cutting Depth ◽  
Lump Coal ◽  
Spiral Angle ◽  
Element Method

Drum of Shearer undertakes the main function of coal falling and loading, and its performance directly affects the working efficiency of the shearer. Therefore, in order to realize the analysis of the performance of the shearer drum, the MG2 × 55/250-BW shearer drum was the engineered object. Combining the physical and mechanical properties experiment results of coal samples, the coupling model of the drum cutting in complex coal seam was established using discrete element method. The falling-coal characteristics of the spiral drum were studied under different working conditions, and the falling-coal trajectories of the coal and rock particles were fitted. Based on a virtual prototype, the variations of the coal loading rate and lump coal rate with different design parameters were determined by studying the falling-coal effect and loading performance of the drum. Considering the drum performance, multi-objective optimization theory was used to determine the optimal operating and structural parameters. The results indicate that, in the process of drum cutting, the cutting depth has the most significant effect on the coal loading rate, while, the blade spiral angle has the least significant. Moreover, with the increase of the cutting depth of drum and the traction speed, the lump coal rate increases. While, with the increase of the drum rotation speed and the blade spiral angle, the lump coal rate decreases. It is found that when the cutting depth of the drum is 597 mm, the traction speed is 5.4 m/min, the drum rotation speed is 104.8 r/min, and the blade spiral angle is 12° the performance of the drum is optimal. Compared with the falling-coal trajectories before optimization, the displacements of the coal and rock particles ejected along the optimal falling-coal trajectories increase in the coal loading direction. The loading rate and lump coal rate of the drum increase by 6.05% and 12.27%, respectively. The load fluctuation of the drum decreases, and the productivity increases.

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.

Combined Sliding Mode Control with a Feedback Linearization for Speed Control of Induction Motor

2011 ◽  
Vol 7 (1) ◽  
pp. 19-24
Author(s):  
Aamir Hashim Obeid Ahmed ◽  
Martino O. Ajangnay ◽  
Shamboul A. Mohamed ◽  
Matthew W. Dunnigan
Keyword(s):  
Sliding Mode Control ◽  
Induction Motor ◽  
Feedback Linearization ◽  
Sliding Mode ◽  
Speed Control ◽  
Mode Control
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