scholarly journals Effects of Focus Geometry on the Hard Rock-Cutting Performance of an Abrasive Waterjet

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Yohan Cha ◽  
Tae-Min Oh ◽  
Gye-Chun Cho
Keyword(s):  
Momentum Transfer ◽  
Hard Rock ◽  
Empirical Relationship ◽  
Abrasive Particle ◽  
Rock Cutting ◽  
Maximum Energy ◽  
Cutting Performance ◽  
Granitic Rocks ◽  
Abrasive Waterjet ◽  
Cutting Depth

Abrasive waterjets are being increasingly used in civil engineering for rock and concrete cutting, particularly for the demolition or repair of old structures. The energy of an abrasive waterjet is primarily provided by the accelerated abrasive. The momentum transfer during mixing and acceleration determines the abrasive velocity, which affects the cutting performance. Meanwhile, the geometry of the focus at which mixing occurs influences the momentum transfer efficiency. In this study, the effects of the focus geometry on the optimum abrasive flow rate (AFR) and momentum transfer characteristics in hard rock cutting were investigated. Experiments were conducted using granite specimens to test the AFR under different focus geometry conditions such as diameter and length. The results show that the focus geometry significantly affects the maximum cutting depth and optimum AFR. The maximum cutting energy was analyzed based on the cutting efficiency of a single abrasive particle. In addition, the momentum transfer parameter (MTP) was evaluated from the empirical relationship between the maximum energy and the cutting depth for granitic rocks. Accordingly, a model for estimating the MTP based on the AFR was developed. It is expected that the results of this study can be employed for the optimization of waterjet rock cutting.

scholarly journals Simple Approach for Evaluation of Abrasive Mixing Efficiency for Abrasive Waterjet Rock Cutting

2021 ◽  
Vol 11 (4) ◽  
pp. 1543
Author(s):  
Yohan Cha ◽  
Tae-Min Oh ◽  
Hyun-Joong Hwang ◽  
Gye-Chun Cho
Keyword(s):  
Flow Rate ◽  
Particle Density ◽  
Empirical Relationship ◽  
Cost Effective ◽  
Rock Cutting ◽  
Cutting Performance ◽  
Abrasive Waterjet ◽  
Mixing Efficiency ◽  
Abrasive Waterjets ◽  
Design Selection

The abrasive mixing variables, such as the abrasive and water flow rates and the focus geometry parameters, determine the profitability of an abrasive waterjet system. In this study, the mixing efficiency characteristics in abrasive waterjet rock cutting were investigated. To demonstrate comprehensively the efficiency reduction due to collision during abrasive mixing, the chance of collision was expressed as the distance between the abrasive particles in the focus. The mixing efficiency was then assessed by utilizing the empirical relationship between the experimental results and the developed model. Based on the particle density and the velocity, the closer particles showed higher chances of collision, thus yielding a reduced cutting performance. Using the distance between particles model, the optimum abrasive flow rate and the cutting performance of abrasive waterjet systems can be estimated. This developed model can be used for the design selection of abrasive flow rate and systems for the cost-effective use of abrasive waterjets.

Effect of Abrasive Feed Rate on Rock Cutting Performance of Abrasive Waterjet

2019 ◽  
Vol 52 (9) ◽  
pp. 3431-3442 ◽  
Author(s):  
Tae-Min Oh ◽  
Gun-Wook Joo ◽  
Gye-Chun Cho
Keyword(s):  
Feed Rate ◽  
Rock Cutting ◽  
Cutting Performance ◽  
Abrasive Waterjet

scholarly journals Effect of Garnet Characteristics on Abrasive Waterjet Cutting of Hard Granite Rock

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tae-Min Oh ◽  
Gun-Wook Joo ◽  
Yohan Cha ◽  
Gye-Chun Cho
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Rock Cutting ◽  
Cutting Performance ◽  
Abrasive Waterjet ◽  
Test Results ◽  
Abrasive Particles ◽  
Waterjet Cutting ◽  
Abrasive Waterjet Cutting

Abrasive waterjet cutting technology has come back into use in the field of rock excavation (such as for tunneling) due to the need for precision construction with low vibration. Because the abrasive particles play an important role in efficient erosion during the cutting process, the abrasive characteristics strongly affect the rock cutting performance. In this study, rock cutting tests were performed with five different coarse (40 mesh) garnets to explore the effect of the abrasive feed rate, physical properties, and particle size distribution on rock cutting performance. In addition, garnet particle disintegration was investigated with garnet characteristics for the abrasive waterjet. The test results indicate that the particle size distribution, garnet purity, specific gravity, and hardness are the most important parameters for rock cutting performance. This study offers better understanding of coarse garnet performance and efficiency according to the garnet characteristics. This should provide assistance in selection of the garnet needed to achieve the desired performance for hard rock cutting.

scholarly journals Numerical Simulation of Rock Cutting with a Diamond Sawblade Based on LS-DYNA

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Zhiwen Wang ◽  
Qingliang Zeng ◽  
Zhenguo Lu ◽  
Lirong Wan ◽  
Xin Zhang
Keyword(s):  
Numerical Simulation ◽  
Hard Rock ◽  
Great Influence ◽  
Cutting Parameters ◽  
Rock Cutting ◽  
Feed Speed ◽  
Specific Cutting Energy ◽  
Cutting Depth ◽  
Cutting Energy ◽  
Diamond Sawblade

Aiming at the complex nonlinear dynamic problem of cutting hard rock with diamond sawblades, the process of hard rock cutting with a diamond sawblade was studied based on ANSYS/LS-DYNA. A numerical simulation model of a diamond sawblade cutting hard rock with different rotation speeds, feed speeds, and cutting depths was established to study the effects of the cutting parameters on the cutting force and specific cutting energy consumption and on the damage to the rock. The numerical simulation results demonstrated that the feed speed and cutting depth of the diamond saw are quadratically correlated with the cutting force, but the rotation speed is negatively linearly correlated. The damage region of the rock is positively correlated with the feed speed and cutting depth of the diamond sawblade and has a negative correlation with the rotation velocity. The cutting parameters have a great influence on specific cutting energy consumption. Analysis of the relationship among the cutting parameters and the specific cutting energy with multivariate linear fitting indicated that the cutting speed and cutting depth have a great influence on the cutting energy.

scholarly journals Performance and Reuse of Steel Shot in Abrasive Waterjet Cutting of Granite

2021 ◽  
Author(s):  
Yohan Cha ◽  
Tae-Min Oh ◽  
Gun-Wook Joo ◽  
Gye-Chun Cho
Keyword(s):  
Particle Size ◽  
Industrial Waste ◽  
High Hardness ◽  
Rock Cutting ◽  
Cutting Performance ◽  
Abrasive Waterjet ◽  
Steel Shot ◽  
Abrasive Surface ◽  
The Cost ◽  
Recycled Steel

AbstractSteel shots are suitable for abrasive waterjet rock cutting and recycling because of the high hardness and magnetic properties of steel. This study evaluated the rock-cutting performance and recycling characteristics of steel shot waterjet. The rock-cutting responses of steel shot and garnet were compared at the same waterjet conditions. The used steel shot was collected and the particle-size changes were evaluated before reuse, and its cutting performance was re-evaluated. Overall, the steel shot waterjet yielded improvements in performance in the range of 30–50% compared with the garnet waterjet. Moreover, the recycled steel shot yielded a 50% reduction in cutting performance. Rust was observed on the surface of the used steel shot, the used steel shots were partially destroyed, and the debris on the abrasive surface needed to be removed by drying. The reusable steel shot left on the 80th sieve converged to 60% in each recycling run. The results of this study can be used to reduce the cost of abrasive waterjet and industrial waste.

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 Parameter Optimization of Polishing M300 Mold Steel with an Elastic Abrasive

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Xiao-Jun Wu ◽  
Xin Tong ◽  
Hao Sun ◽  
Huibo Jia ◽  
Lu Zhang
Keyword(s):  
Particle Size ◽  
Rotational Speed ◽  
Abrasive Particle ◽  
Polished Surface ◽  
Feed Speed ◽  
Range Analysis ◽  
Cutting Depth ◽  
Surface Polishing ◽  
Optimum Parameters ◽  
Influence Degree

In order to achieve high-quality polishing of M300 mold steel curved surface, an elastic abrasive is introduced in this paper, and its polishing parameters are optimized so that the mirror roughness can be achieved. Based on the Preston equation and Hertz contact theory, the theoretical material removal equation for surface polishing of elastic abrasives is obtained, and the polishing parameters to be optimized are as follows: particle size S, rotational speed Wt, cutting depth Ap, and feed speed Vf. The Taguchi method is applied to design the orthogonal experiment with four factors and three levels. The influence degree of various factors on the roughness of the polished surface and the combination of parameters to be optimized were obtained by the range analysis method. The particle swarm optimization algorithm optimizes the BP neural network algorithm (PSO-BP), which is used to optimize the polishing parameters. The results show that the rotational speed has the greatest influence on the roughness, the influence degree of abrasive particle size is greater than that of feed speed, and the influence of cutting depth is the least. The optimum parameters are as follows: particle size S 1200#, rotational speed Wt 4500rpm, cutting depth Ap 0.25mm, and feed speed Vf 0.8mm/min. The roughness of the surface polishing with optimum parameters is reduced to 0.021 μm.

scholarly journals Influence of Traverse Velocity and Pump Pressure on the Efficiency of Abrasive Waterjet for Rock Cutting

2017 ◽  
Vol 40 (3) ◽  
pp. 255-262 ◽  
Author(s):  
Paola Bruno Arab ◽  
Tarcísio Barreto Celestino
Keyword(s):  
Rock Cutting ◽  
Abrasive Waterjet ◽  
Pump Pressure
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