Study on Machining Mechanism of Glass Using Discrete Element Method

2014 ◽  
Vol 577 ◽  
pp. 108-111 ◽  
Author(s):  
Ying Qiu ◽  
Mei Lin Gu ◽  
Feng Guang Zhang ◽  
Zhi Wei

The discrete element method (DEM) is applied to glass micromachining in this study. By three standard tests the discrete element model is established to match the main mechanical properties of glass. Then, indentating, cutting, micro milling process are simulated. Results show that the vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkable factor influencing on the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thickness per edge. Different cutting thickness, cutter shape and spindle speed largely effect on the mechanism of glass.

2013 ◽  
Vol 300-301 ◽  
pp. 1304-1308
Author(s):  
Liang Kang ◽  
Yong Ye

The discrete element model and the model of single diamond grain grinding process of granite were constructed through numerical simulation and calibration of mechanical properties. Based on the models, the grinding processes of granite was dynamically simulated, and the effects of different rank angles, grinding speeds and cutting depths on the distribution of residual stresses as the depth of workpiece were also analyzed. The results show that the residual stress in the workpiece is relatively small after grinding when the tool rank angle lays in a small negative (-200 to 00). Otherwise, when the tool rank angle is too large or too small, there is a significant residual stress. The residual stresses in the workpiece increase with the increase of grinding speed and cutting depth. The residual stress nephogram was accomplished and the generated mechanism of residual stress was also analyzed. The results proved that the discrete element method (DEM) is an effective way to analyze the residual stress


Author(s):  
Anders H. Andersen ◽  
Frederik F. Foldager ◽  
Kasper Ringgaard ◽  
Ole Balling

Production of high accuracy components often involves machining processes. If the machining processes are pushed to increase productivity, it can become challenging to comply with strict tolerances and surface finish requirements. Both the finite element method and the discrete element method have been used for off-line deflection compensation and stability analysis. This contribution investigates the capabilities of a simplified discrete element model in the use for offline simulation of the dynamic behavior of a workpiece during machining. A cantilever beam is modelled and the natural frequencies are monitored as material is removed. Results are compared with theoretical frequencies and with finite element analysis. The model shows a good correspondence in the frequency behavior as material is removed compared with finite element results, though the simple discrete element model under-predicts the stiffness of the beam with approximate 5% for the first two modes.


2014 ◽  
Vol 556-562 ◽  
pp. 1200-1204 ◽  
Author(s):  
Li Wu ◽  
Chang Liu

To discover the interaction rules between the cutterhead of shield machine and the soils, the model experiment of shield machine tunneling is performed, and the particle discrete element model of the experiment is built. By adjusting the particle parameters, the simulated cutterhead torque is compatible with the experiment observed results. Then the displacement of soils in the front of the cutterhead, behind the cutterhead, and in the front of the chamber board is obtained. The soils in the front of the cutterhead try to flow into the nearest opening. However, the soils behind the cutterhead move toward the wall of out barrel. The movement of soils in front of the chamber board is in accordance with the rotation direction of the cutterhead.


2021 ◽  
pp. 014459872110135
Author(s):  
Zhen Tian ◽  
Shuangxi Jing ◽  
Lijuan Zhao ◽  
Wei Liu ◽  
Shan Gao

The drum is the working mechanism of the coal shearer, and the coal loading performance of the drum is very important for the efficient and safe production of coal mine. In order to study the coal loading performance of the shearer drum, a discrete element model of coupling the drum and coal wall was established by combining the results of the coal property determination and the discrete element method. The movement of coal particles and the mass distribution in different areas were obtained, and the coal particle velocity and coal loading rate were analyzed under the conditions of different helix angles, rotation speeds, traction speeds and cutting depths. The results show that with the increase of helix angle, the coal loading first increases and then decreases; with the increase of cutting depth and traction speed, the coal loading rate decreases; the increase of rotation speed can improve the coal loading performance of drum to a certain extent. The research results show that the discrete element numerical simulation can accurately reflect the coal loading process of the shearer drum, which provides a more convenient, fast and low-cost method for the structural design of shearer drum and the improvement of coal loading performance.


2018 ◽  
Vol 171 ◽  
pp. 1-15 ◽  
Author(s):  
James B. Barr ◽  
Mustafa Ucgul ◽  
Jack M.A. Desbiolles ◽  
John M. Fielke

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yuwan Yang ◽  
Mo Li ◽  
Jin Tong ◽  
Yunhai Ma

A mole is a born digger spending its entire existence digging tunnels. The five claws of a mole’s hand are combinative to cut soil powerfully and efficiently. However, little was known in detail about the interaction between the soil and the five-claw combination. In this study, we simulated the soil cutting process of the five-claw combination using the discrete element method (DEM) as an attempt for the potential design of soil-engaging tools to reduce soil resistance. The five-claw combination moved horizontally in the soil bin. Soil forces (draught and vertical forces) and soil failure (soil rupture distance ratio) were measured at different rake angles and speeds. Results showed that the draught and vertical forces varied nonlinearly as the rake angle increased from 10 to 90°, and both changed linearly with the speed increasing from 1 to 5 m/s. The curve of the soil rupture distance ratio with rake angles could be better described using a quadric function, but the speed had little effect on the soil rupture distance ratio. Notably, the soil rupture distance ratio of the five-claw combination in simulation was on average 19.6% lower than the predicted ratio of simple blades at different rake angles indicating that the five-claw combination could make less soil failure and thereby produce lower soil resistance. Given the draught and vertical forces, the performance of the five-claw combination was optimized at the rake angle of 30°.


2005 ◽  
Vol 128 (3) ◽  
pp. 439-444 ◽  
Author(s):  
Harald Kruggel-Emden ◽  
Siegmar Wirtz ◽  
Erdem Simsek ◽  
Viktor Scherer

The discrete element method can be used for modeling moving granular media in which heat and mass transport takes place. In this paper the concept of discrete element modeling with special emphasis on applicable force laws is introduced and the necessary equations for heat transport within particle assemblies are derived. Possible flow regimes in moving granular media are discussed. The developed discrete element model is applied to a new staged reforming process for biomass and waste utilization which employs a solid heat carrier. Results are presented for the flow regime and heat transport in substantial vessels of the process.


2016 ◽  
Vol 302 ◽  
pp. 350-356 ◽  
Author(s):  
Abhay Patwa ◽  
R.P. Kingsly Ambrose ◽  
Mark.E. Casada

2013 ◽  
Vol 568 ◽  
pp. 49-54
Author(s):  
H.B. Wu ◽  
Q.P. Sun ◽  
Dun Wen Zuo

Discrete element model of fully sintering dental zirconia was constructed and calibrated. Based on the model, the dynamic process of low-speed milling of zirconia was simulated, and the effects of different cutting speeds, cutting widths and federates on the formation of surface cracks were also analyzed. Results show that residue cracks number and maximum depth increases significantly with increase of the cutting width, while the influence of cutting speed and federates is not distinct. That shows the possibility of high-speed machining on fully sintering dental zirconia with development of coating technology of cutting tool.


Author(s):  
Weipan Xu ◽  
Haiyang Zeng ◽  
Peng Yang ◽  
Mengyan Zang

The interaction between off-road tires and granular terrain has a great influence on the tractive performance of off-road vehicles. However, the finite element method or the discrete element method cannot effectively study the interaction between off-road tires and granular terrain. The three-dimensional combined finite element and discrete element method is applied to handle this problem. In this study, a calibrated finite element method–discrete element method model is established, in which the finite element model of off-road tire is validated by stiffness tests, while the discrete element model of gravel particles is validated by triaxial compression tests. The calibrated finite element method–discrete element method model can describe the structural mechanics of the off-road tire and the macroscopic mechanical properties of the gravel road. Tractive performance simulations of the off-road tire on gravel road under different slip conditions are performed with the commercial software LS-DYNA. The simulation results are basically corresponded with the soil-bin test results in terms of granular terrain deformation and tractive performance parameters versus the slip rates. Finally, the effects of tread pattern, wheel load, and tire inflation pressure on tractive performance of off-road tire on granular terrain are investigated. It indicates that the calibrated finite element method–discrete element method can be an effective tool for studying the tire–granular terrain interaction and predicting the tractive performance of off-road tire on granular terrain.


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