scholarly journals Investigation of the influence mechanism of rock damage on rock fragmentation and cutting performance by the discrete element method

2019 ◽  
Vol 6 (5) ◽  
pp. 190116 ◽  
Author(s):  
Si-fei Liu ◽  
Shuai-feng Lu ◽  
Zhi-jun Wan ◽  
Jing-yi Cheng
Keyword(s):  
Cutting Force ◽  
Rock Cutting ◽  
Rock Breaking ◽  
Pulse Number ◽  
Rock Fragmentation ◽  
Cutting Performance ◽  
Tensile Failure ◽  
Rock Damage ◽  
Damage Factor ◽  
Mining Machinery

Rock damage is one of the key factors in the design and model choice of mining machinery. In this paper, the influence of rock damage on rock fragmentation and cutting performance was studied using PFC 2D . In PFC 2D software, it is feasible to get rock models with different damage factors by reducing the effective modulus, tensile and shear strength of bond by using the proportional factors. A linear relationship was obtained between the proportion factor and damage factor. Furthermore, numerical simulations of rock cutting with different damage factors were carried out. The results show that with the increase of damage factor, the rock cutting failure mode changes from tensile failure to brittle failure, accompanied by the propagation of macro cracks, the formation of large debris and a notable decrease in the peak cutting force. The mean cutting force is negatively correlated with the damage factor. Besides this, the instability of cutting force was evaluated by the fluctuation index and the pulse number of unit displacement. It was found that the cutting force was quite stable when the damage factor was 0.3, which improves the reliability of cutting machines. Finally, the cutting energy consumption of rock cutting with different damage factors was analysed. The results reveal that an increase of damage factor can raise the rock cutting efficiency. The aforementioned findings play a significant role in the development of assisted rock-breaking technologies and the design of cutting head layout of mining machinery.

scholarly journals Numerical Simulation of Rock Plate Cutting with Three Sides Fixed and One Side Free

2018 ◽  
Vol 2018 ◽  
pp. 1-21 ◽  
Author(s):  
Zhenguo Lu ◽  
Lirong Wan ◽  
Qingliang Zeng ◽  
Xin Zhang ◽  
Kuidong Gao
Keyword(s):  
Numerical Simulation ◽  
Cutting Force ◽  
Cutting Speed ◽  
Rock Cutting ◽  
Numerical Results ◽  
Peak Force ◽  
Cutting Performance ◽  
Conical Pick ◽  
Cutting Method ◽  
Cutting Angle

In order to overcome conical pick wear in the traditional rock cutting method, a new cutting method was proposed on account of increasing free surface of the rock. The mechanical model of rock plate bending under concentrated force was established, and the first fracture position was given. The comparison between experimental and numerical results indicated that the numerical method is effective. A computer code LS-DYNA (3D) was employed to study the cutting performance of a conical pick. To study the rock size influenced on the cutting performance, the numerical simulations with different thickness, width, and height of a rock plate was carried out. The numerical simulation with the different cutting parameters of cutting speed, cutting angle, and cutting position influenced on cutting performance was also carried out. The numerical results indicated that the peak force increased with the increasing thickness of rock plate. With the increasing width and height of the rock plate, the peak force decreased and then became stable. Besides, the peak force decreased with the increasing of cutting position lxp/lx. Moreover, the peak force increased and then decreased with the increasing of cutting angle. The cutting speed has nonsignificant influence on the peak force. The strong exponential relationship was obtained between the peak force and cutting position, thickness, height, and width of the rock plate at a confidence level of 0.95. A binomial relationship was observed between the peak force and cutting angel. The cutting force comparison between traditional rock cutting and rock plate cutting indicated that the new cutting method can effectively reduce peak cutting force.

scholarly journals Numerical Simulation of the Influence of the Distance between the Diamond Sawblade and Free Surface on Cutting Performance

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qingliang Zeng ◽  
Zhiwen Wang ◽  
Zhenguo Lu ◽  
Lirong Wan ◽  
Xin Zhang
Keyword(s):  
Numerical Simulation ◽  
Free Surface ◽  
Cutting Force ◽  
Tangential Force ◽  
Surface Damage ◽  
Cutting Performance ◽  
Feed Speed ◽  
Rock Damage ◽  
Cutting Depth ◽  
Diamond Sawblade

The diamond sawblade has been widely used in the field of rock mining and processing. This article, through the establishment of a numerical simulation model of diamond sawblade cutting rock, studies the influence of the distance between the diamond sawblade and free surface on cutting performance. In the process of diamond sawblade cutting rock, with the increase of the distance from the sawblade to the free surface, the average cutting force, normal force, and tangential force of the sawblade increase at first and then stabilize, and the axial force gradually decreases and tends to be stable. In the process of cutting rock with fixed depth, cutting force and rock damage are positively related to feed speed and cutting depth of the diamond sawblade. Through the statistical analysis of rock damage by image recognition program statistics, it is concluded that the feed speed and cutting depth of the sawblade have a significant impact on the rock damage value. When the distance increases to 12 mm, there is a relatively complete rock plate between the sawblade and free surface. The rock free surface damage disappears when distance reaches 16 mm. The research results provide a theoretical basis for the sawblade processing rock plate.

scholarly journals A study on the influence of pick geometry on rock cutting based on full-scale cutting test and simulation

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402097449
Author(s):  
Xuefeng Li
Keyword(s):  
Shear Failure ◽  
Cutting Parameters ◽  
Rock Cutting ◽  
Rake Angle ◽  
Full Scale ◽  
Cutting Performance ◽  
Tensile Failure ◽  
General Process ◽  
Multiple Attribute ◽  
Cutting Simulations

In this paper, series of full-scale cutting tests and cutting simulations are carried out to investigate the influence of installation parameter and geometry of the pick on cutting performance. The discrete element method is used to simulate the rock cutting process. A general process to calibrate macro properties of rock including uniaxial compressive strength (UCS), elastic modulus, Poisson’s ratio, cohesion and internal friction angle is proposed and used to complete the calibration of coal model. The cutting simulations are performed using picks with different tip angles and rake angles. The results show that the peak cutting force (PCF) decreases with the increase of rake angle following an inverse proportional function when the rake angle is positive, while it varies following a parabolic curve in the condition of negative rake angle. Moreover, the crack mode changes from primarily shear failure to primarily tensile failure with the increase of rake angle. Finally, a multiple-attribute index is proposed to evaluate the cutting performance and select the optimum cutting parameters.

scholarly journals Numerical Investigation of the Rock Cutting Performance of a Circular Sawblade

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhiwen Wang ◽  
Qingliang Zeng ◽  
Zhenguo Lu ◽  
Zhihai Liu ◽  
Xu Li
Keyword(s):  
Cutting Force ◽  
Great Influence ◽  
Cutting Parameters ◽  
Simulation Method ◽  
Rock Cutting ◽  
Rock Breaking ◽  
Feed Speed ◽  
Specific Cutting Energy ◽  
Cutting Depth ◽  
Cutting Energy

The rock cutting process with a circular sawblade and the rock breaking mechanism of rock are studied with a numerical simulation method in this paper. The influence of cutting parameters of the circular sawblade on cutting force, rock damage, and specific cutting energy in the process of circular sawblade cutting rock is researched. The cutting force increases with the feed speed and an increase in cutting depth and decline in rotation speed. Cutting rock with double circular sawblades can reduce cutting force. However, the specific cutting energy declines with the increase in cutting depth and the decline in the distance between the double circular sawblades. Cutting parameters have a great influence on the damage range of rock. The research results can be applied to rock processing with a circular sawblade.

scholarly journals Experimental and Numerical Studies on Rock Cutting with Saw Blade and Conical Pick Combined Cutting Method

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Zhenguo Lu ◽  
Qingliang Zeng ◽  
Zhiwen Wang ◽  
Xu Li ◽  
Kuidong Gao
Keyword(s):  
Cutting Force ◽  
Element Model ◽  
Rock Cutting ◽  
Mechanical Tests ◽  
Cutting Performance ◽  
Physical Parameters ◽  
Plate Height ◽  
Conical Pick ◽  
Cutting Method ◽  
Positive Correlation

In the rock cutting process, conical pick wear is often encountered. In order to restrain this condition, a saw blades and conical pick combined cutting method was put forward. Saw blades were employed to slit the rock for increasing the free surface, and then the conical pick was used to break the rock. To research the cutting performance of the new cutting method, the corresponding experimental device and a three-dimensional finite element model are established. In order to obtain crack propagation and fragment separation and to study the fracture process of the rock plate, a damage constative model and failure mechanism were combined in the numerical model. The mechanical tests were carried out to achieve the mechanical parameters of the rock. To investigate different parameters affecting rock plate cutting performance, experiments with different compressive strengths, physical parameters, and cutting depths were carried out. Moreover, the confining pressures affecting the cutting performance were adopted to simulate deep mining conditions. The experimental results demonstrated that the peak cutting force shows the exponential positive correlation with compressive strength, thickness of the rock plate, and cutting depth of the conical pick, and exhibits the exponential positive correlation with rock plate height and width. Besides, the numerical simulation results show that peak cutting force and confining pressure have a binomial relationship.

The Analysis of the Parameters of Rock Cutting by Disc Cutter Based on ANSYS

2013 ◽  
Vol 791-793 ◽  
pp. 778-781
Author(s):  
An Ning Zhang ◽  
Feng Zhu ◽  
Zhao Feng Zhu
Keyword(s):  
Yield Criterion ◽  
Element Model ◽  
Rock Cutting ◽  
Rock Breaking ◽  
Disc Cutter ◽  
Vertical Force ◽  
Rock Damage ◽  
Plastic Yield ◽  
Rock Mechanical Properties ◽  
Tbm Cutter

When TBM tunneling, the disc cutter directly in contact with the rock. The disc cutter is an important component of the TBM, so the numerical simulation study of disc cutter breaking rock process is established. The study contents disc cutter exerted vertical force on the rock. This is instructive for improving the disc cutter layout and improving the rock breaking capacity and tunneling efficiency. According to the rock Drucker-Prager plastic yield criterion lines and rock mechanical properties, finite element model of rock breaking by disc cutter was established by ANSYSWORKBENCH software and process of rock cutting with disc cutter was simulated. The rock elastic-plastic deformation occurred in the disc cutter effect, caused accumulation of rock damage, when the rock breaks completely damaged, get the vertical force exerted on the disc cutter, which is significance for the disc cutter layout and the calculation of force of TBM cutter breaking rock.

scholarly journals An Analytical Model for Rock Cutting with a Chisel Pick of the Cutter Suction Dredger

2020 ◽  
Vol 8 (10) ◽  
pp. 806
Author(s):  
Yiping Ouyang ◽  
Qi Yang ◽  
Xinquan Chen ◽  
Yongfu Xu
Keyword(s):  
Cutting Force ◽  
Analytical Model ◽  
Cutting Parameters ◽  
Theoretical Models ◽  
Rock Cutting ◽  
Rake Angle ◽  
Experimental Results ◽  
Tensile Failure ◽  
Cavity Expansion Theory ◽  
Sidewall Effect

Cutter suction dredgers are important pieces of rock excavation equipment in port and waterway construction. It is valuable but difficult to properly estimate the cutting force on the chisel pick of the cutter suction dredger. In this paper, an analytical model, called the crushed zone expansion induced tensile failure model (CEIT model), is proposed for rock cutting with a chisel pick in order to predict the peak cutting force (Fc) more accurately. First, a review of the existing models for rock cutting with a chisel pick is presented. Next, based on the tensile breakage theory, cavity expansion theory and some hypotheses, the mathematical formula of the CEIT model is obtained. Different from that in the previous models, the effect of the rock on both sides of the chisel pick on Fc, defined as the sidewall effect is considered in the CEIT model. Then, the predicted Fc by the CEIT model is compared with the predicted Fc by existing theoretical models and experimental results to check the validity of the CEIT model. The results show that the CEIT model can well capture the relationships of Fc to the cutting parameters, including cutting width, cutting depth, and rake angle, and can predict the experimental results much better than the existing models. Finally, the sidewall effect and its influence factors according to the CEIT model are discussed.

scholarly journals The Comparative Study on Cutting Performance of Different-Structure Milling Cutters in Machining CFRP

2018 ◽  
Vol 8 (8) ◽  
pp. 1353
Author(s):  
Tao Chen ◽  
Fei Gao ◽  
Suyan Li ◽  
Xianli Liu
Keyword(s):  
Carbon Fiber ◽  
Cutting Force ◽  
Surface Quality ◽  
Cutting Edge ◽  
Cutting Performance ◽  
Machining Process ◽  
Carbon Fiber Composites ◽  
Machined Surface ◽  
Milling Cutter ◽  
Machined Surface Quality

Carbon fiber reinforced plastic (CFRP) is typically hard to process, because it is easy for it to generate processing damage such as burrs, tears, delamination, and so on in the machining process. Consequently, this restricts its wide spread application. This paper conducted a comparative experiment on the cutting performance of the two different-structure milling cutters, with a helical staggered edge and a rhombic edge, in milling carbon fiber composites; analyzed the wear morphologies of the two cutting tools; and thus acquired the effect of the tool structure on the machined surface quality and cutting force. The results indicated that in the whole cutting, the rhombic milling cutter with a segmented cutting edge showed better wear resistance and a more stable machined surface quality. It was not until a large area of coating shedding occurred, along with chip clogging, that the surface quality decreased significantly. At the stage of coating wear, the helical staggered milling cutter with an alternately arranged continuous cutting edge showed better machined surface quality, but when the coating fell off, its machined surface quality began to reveal damage such as groove, tear, and fiber pullout. Meanwhile, burrs occurred at the edge and the cutting force obviously increased. By contrast, for the rhombic milling cutter, both the surface roughness and cutting force increased relatively slowly.

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