scholarly journals Effect of Abrasive Concentration on Impact Performance of Abrasive Water Jet Crushing Concrete

2019 ◽  
Vol 2019 ◽  
pp. 1-18
Author(s):  
Xiaohui Liu ◽  
Ping Tang ◽  
Qi Geng ◽  
Xuebin Wang
Keyword(s):  
Internal Energy ◽  
Impact Force ◽  
Abrasive Particle ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Sph Method ◽  
Impact Performance ◽  
Water Jets ◽  
The Impact ◽  
Peak Impact Force

It has been found that the impact performance of water jets can be changed by its properties, which include pressure, additive, and mode of jet. Thus, an abrasive water jet (AWJ) has been developed as a new method. However, there is little research on the effect of abrasive concentration on the impact performance of abrasive jets. Thus, the SPH method is used to establish an abrasive water jet crushing concrete model to study the effect of abrasive concentration on the impact force, concrete internal energy, abrasive particle distribution, crushing depth, and damage and crushing efficiencies under different concrete compressive strengths and abrasive densities. The results indicate that there is little effect of the abrasive concentration on the peak impact force under different compressive strengths and abrasive densities, while the mean impact force tends to increase linearly with the abrasive concentration. The internal energy of the concrete increases stepwise with the abrasive concentration under different compressive strengths and abrasive densities. The concentration of 10%∼20% is the rapid increasing stage. The crushing depth and damage efficiencies are all maximum at a concentration of 20% under different compressive strengths and abrasive densities. After the concrete was impacted by the water from the water jet, it is divided into rebounding particles and intrusive particles. The more the intrusive particles, the easier the concrete to be crushed and damaged.

An experimental and simulation study of the flow pattern characteristics of water jet impingements in boreholes

2021 ◽  
pp. 014459872110520
Author(s):  
Yabin Gao ◽  
Xin Xiang ◽  
Ziwen Li ◽  
Xiaoya Guo ◽  
Peizhuang Han
Keyword(s):  
High Speed ◽  
Impact Force ◽  
Jet Impingement ◽  
Flow Patterns ◽  
Water Jet ◽  
Solid Boundary ◽  
Force Model ◽  
Water Jets ◽  
Contact Surfaces ◽  
The Impact

Hydraulic slotting has become one of the most common technologies adopted to increase permeability in low permeability in coal field seams. There are many factors affecting the rock breaking effects of water jets, among which the impact force cannot be ignored. To study the influencing effects of contact surface shapes on jet flow patterns and impact force, this study carried out experiments involving water jet impingement planes and boreholes under different pressure conditions. The investigations included numerical simulations under solid boundary based on gas–liquid coupling models and indoor experiments under high-speed camera observations. The results indicated that when the water jets impinged on different contact surfaces, obvious reflection flow occurred, and the axial velocity had changed through three stages during the development process. Moreover, the shapes of the contact surfaces, along with the outlet pressure, were found to have impacts on the angles and velocities of the reflected flow. The relevant empirical formulas were summarized according to this study's simulation results. In addition, the flow patterns and shapes of the contact surfaces were observed to have influencing effects on the impact force. An impact force model was established in this study based on the empirical formula, and the model was verified using both the simulation and experimental results. It was confirmed that the proposed model could provide important references for the optimization of the technical parameters water jet systems, which could provide theoretical support for the further intelligent and efficient transformation of coal mine drilling water jet technology.

Force attenuation capacity of weft-knitted spacer fabric in low-velocity impact

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ryan Rudy ◽  
Wiah Wardiningsih
Keyword(s):  
Impact Force ◽  
Test Method ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Content Type ◽  
Impact Performance ◽  
Spacer Fabric ◽  
Spacer Fabrics ◽  
The Impact ◽  
Peak Impact Force

PurposeThis study aimed to determine the peak impact force and force attenuation capacity of weft-knitted spacer fabrics intended for padding that can be used for human body protection against impact.Design/methodology/approachA total of five weft-knitted spacer fabrics were fabricated with four different diameters of nylon monofilament yarns and one doubled monofilament yarns, respectively. The impact performances of the weft-knitted spacer fabrics were tested using a drop test method with a customized test rig to simulate falling. Impact tests were conducted on single- and multilayered experimental spacer fabrics to investigate the peak impact force and force attenuation capacity.FindingsIt was found that weft-knitted spacer fabric with a coarser or larger diameter of monofilament spacer yarn generated lower impact force and higher force attenuation capacity, thus resulting in better impact performance. Greater force attenuation can be achieved by utilizing a higher number of spacer fabric layers. However, the increase in thickness must be considered with the spacer fabric end use.Originality/valueThis study employed relatively coarse nylon monofilament yarn as spacer yarns to gain knowledge on the impact performance of weft-knitted spacer fabrics compared to warp-knitted spacer fabrics which are more common. The results showed that the diameter of spacer yarn significantly influenced the impact performance of the experimental weft-knitted spacer fabrics. These results could be useful for designing and engineering textile-based impact protectors.

Introduction of Premixed Micro-Abrasive Water Jet Technology for Deburring

2014 ◽  
Vol 1027 ◽  
pp. 177-182
Author(s):  
Chun Lin Qiu ◽  
Cheng Yong Wang ◽  
Yue Xian Song
Keyword(s):  
Impact Force ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Jet Formation ◽  
High Productivity ◽  
Residual Damage ◽  
New Type ◽  
The Difference ◽  
High Flexibility ◽  
The Impact

Micro-abrasive water jet technology for deburring is a new type of removing burrs technics with advantages of high productivity, high flexibility, no cutter damage and less residual damage etc, which is applied more and more extensively. This paper introduces the difference of premixed micro-abrasive water jet and post-mixed micro-abrasive water jet on jet formation, the difference of system principles and applications. This paper also provides the formula that how to quantitatively calculate the impact force of water jet. The principles and factors which influence on deburring and some application examples are also described in this paper.

Measuring the Impact Forces within the Cleaning Nozzles Sewage System

2014 ◽  
Vol 657 ◽  
pp. 564-568 ◽  
Author(s):  
Nicolae Medan ◽  
Sándor Ravai Nagy ◽  
Mihai Banica
Keyword(s):  
High Pressure ◽  
Research Method ◽  
Impact Force ◽  
Water Jet ◽  
Rigid Surface ◽  
Sewage System ◽  
Water Jets ◽  
Impact Forces ◽  
Industrial Cleaning ◽  
The Impact

Industrial cleaning is a classic application of water jets technology. In the late 1950s, when reliable high pressure pumps were built, the usage of water jets spread widely in the field of pipes and sewerage cleaning. In our particular case, water jets with less than 340 bar pressure are being used. The experiment is the research method used in the study of the impact forces that occur in the sewerage cleaning head system. In order to measure the impact forces between the water jet and a flat and rigid surface, we designed and built a stand for generating pressure jets, as well as a device to measure the impact force. Using the impact forces measured were calculated the coefficients of discharge, speed and contraction of water jet at the outlet of nozzle.

scholarly journals Analysis and modeling of the effects of process parameters on specific cutting energy in abrasive water jet cutting

2018 ◽  
Vol 22 (Suppl. 5) ◽  
pp. 1459-1470 ◽  
Author(s):  
Predrag Jankovic ◽  
Milos Madic ◽  
Dusan Petkovic ◽  
Miroslav Radovanovic
Keyword(s):  
Mathematical Model ◽  
Process Parameters ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Specific Cutting Energy ◽  
Important Indicator ◽  
Cutting Energy ◽  
Water Jet Cutting ◽  
Abrasive Water Jet Cutting ◽  
The Impact

The problem of cutting difficult-to-machine materials used in the aerospace industry, aircraft industry, and automobile industry, led to the development and application one of today?s most attractive technology for contour cutting - abrasive water jet cutting. For the efficient use of abrasive water jet cutting, it is of great importance to analyze the impact of process parameters on performance indicators, such as cutting quality, productivity, and costs. But also, from the energy utilization point of view, it is very important to analyze the impact of these parameters on the specific cutting energy which represents the amount of energy spent on the removal of material in the unit time. Having this in mind, this study presents the experimental results of abrasive water jet cutting of aluminum alloy with the aim of creating a mathematical model for estimating specific cutting energy as an important indicator of the degree of utilization of the available energy in the cutting process. The mathematical model of the specific cutting energy is explicitly represented as a non-linear function of the process parameters, obtained by the artificial neural network.

scholarly journals Numerical research on impact performance of bridge columns with aluminum foam protection devices

2020 ◽  
Vol 16 (11) ◽  
pp. 155014772097453
Author(s):  
Yuye Zhang ◽  
Ruiyang Pan ◽  
Feng Xiao
Keyword(s):  
Aluminum Foam ◽  
Maximum Stress ◽  
Impact Force ◽  
Bridge Columns ◽  
Design Parameters ◽  
Protection Device ◽  
Impact Performance ◽  
Positive Effects ◽  
Protection Capability ◽  
The Impact

This article presents a new protection device using aluminum foam to enhance the impact resistance of bridge columns. First, the protection device is designed according to the characteristics of aluminum foam material. The geometric configuration and structure of the device are described. Second, the impact performance of bridge column is analyzed, including impact force analysis, damage analysis, and the influence of axial load. Third, three-dimensional solid element models of columns with and without the protection device are developed in order to verify the effect of the protection device. By comparing dynamic responses of vehicle impact on columns with and without the protection device, it is considered that the protection device has certain protection effect: after installing the protective device, the peak value of impact force reduces by 37.5%, the maximum displacement of column top reduces by 23.7%, the maximum stress at column bottom reduces by 51.6%, the maximum stress at column bottom reduces by 51.6%, the maximum acceleration of the vehicle reduces by 40.6%, and 86.84% of the impact energy is absorbed by the protection device. Finally, the devices with different foam thicknesses and porosities are comparatively analyzed to investigate the influence of these design parameters on impact performance. The results show that the increase in the thickness of aluminum foam has positive effects on the protection capability. The protection capability improves with aluminum foam porosity increasing when the porosity is less than 60%.

Dynamic Response and Shear Demand of Reinforced Concrete Beams Subjected to Impact Loading

2019 ◽  
Vol 19 (08) ◽  
pp. 1950091 ◽  
Author(s):  
Wuchao Zhao ◽  
Jiang Qian
Keyword(s):  
Dynamic Response ◽  
Impact Loading ◽  
Parametric Study ◽  
Shear Failure ◽  
Impact Force ◽  
Rc Beams ◽  
Local Response ◽  
Shear Demand ◽  
The Impact ◽  
Peak Impact Force

Reinforced concrete (RC) beams under the impact loading are typically prone to suffer shear failure in the local response phase. In order to enhance the understanding of the mechanical behavior of the RC beams, their dynamic response and shear demand are numerically investigated in this paper. A 3D finite-element model is developed and validated against the experimental data available in the literature. Taking advantage of the above calibrated numerical model, an intensive parametric study is performed to identify the effect of different factors including the impact velocity, impact mass and beam span-to-depth ratio on the impact response of the RC beams. It is found that, due to the inertial effect, a linear relationship exists between the maximum reverse support force and the peak impact force, while negative bending moments also appear in the shear span. In addition, the local response of the RC beams can be divided into a first impact stage and a separation stage. A shear plug is likely to be formed near the impact point at the first impact stage and a shear failure may be triggered near the support by large support forces. Based on the simulation results, simplified methods are proposed for predicting the shear demand for the two failure modes, whereas physical models are also established to illustrate the resistance mechanism of the RC beams at the peak impact force. By comparing with the results of the parametric study, it is concluded that the shear demand of the RC beams under the impact loading can be predicted by the proposed empirical formulas with reasonable accuracy.

The Efficacy of Impact-Absorbing Materials during Collision with a Soccer Ball

2013 ◽  
Vol 440 ◽  
pp. 363-368
Author(s):  
Zahari Taha ◽  
Mohd Hasnun Arif Hassan ◽  
Mohd Azri Aris
Keyword(s):  
High Speed ◽  
Impact Force ◽  
Coefficient Of Restitution ◽  
Soccer Ball ◽  
Absorbing Materials ◽  
The Subject ◽  
The Impact ◽  
The Brain ◽  
Peak Impact Force ◽  
Impact Duration

The uniqueness of soccer is that the players are allowed to use their head to pass the ball to a teammate of even try to score goal. Studies have shown that heading in soccer might be dangerous to the brain and could lead to brain trauma. There are headgears available for soccer players to protect their head, but studies have proven that currently available headgears are ineffective in reducing the impact caused by a soccer ball. The objective of this study is to test the efficacy of six different types of impact-absorbing materials in reducing the linear impact force from a soccer ball. The soccer ball was dropped from the height of 2.3 m onto a force platform to measure the impact force. A high-speed camera is used to record the motion and the impact duration, and then the coefficient of restitution for each impact was determined. Polyurethane (PU) comb-gel was found to be the most effective material in reducing the peak impact force and impulse compared with other materials. The reduction in peak force was associated with longer impact duration between the soccer ball and the PU comb-gel. However, the coefficient of restitution was reduced by 21.7%, implying that using the gel alone will reduce the speed of the ball after heading, thus reducing the performance of a player wearing it. A combination of PU gel and another stiffer material is suggested and the effectiveness of the composite will be the subject of future investigation.

A Study on Erosion of Alumina Wafer in Abrasive Water Jet Machining

2014 ◽  
Vol 1017 ◽  
pp. 228-233 ◽  
Author(s):  
Yong Wang ◽  
Hong Tao Zhu ◽  
Chuan Zhen Huang ◽  
Jun Wang ◽  
Peng Yao ◽  
...  
Keyword(s):  
Process Parameters ◽  
Water Pressure ◽  
Abrasive Particle ◽  
Particle Diameter ◽  
Water Jet ◽  
Abrasive Waterjet ◽  
Abrasive Water Jet ◽  
Alumina Ceramics ◽  
Abrasive Water Jet Machining ◽  
Jet Impact

Abrasive water jet machining is considered as a promising technique in hard and brittle material processing. This paper studies the erosion performance of the alumina ceramics in the different process parameters. In the erosion experiments, alumina ceramics wafers were eroded by the abrasive waterjet machining. The single factor experiments were carried out to understand the effect of different process parameters (jet impact angle, standoff distance, water pressure, abrasive particle diameter) on the material removal rate (MRR), the removal depth and surface roughness (Ra). The experimental results can provide guidance for alumina ceramics abrasive water jet cutting and polishing.

Vibration and Experimental Comparison of Machining Process

2015 ◽  
Vol 669 ◽  
pp. 179-186 ◽  
Author(s):  
Anton Panda ◽  
Marek Prislupčák ◽  
Jozef Jurko ◽  
Iveta Pandová ◽  
Peter Orendáč
Keyword(s):  
Water Jet ◽  
Machining Process ◽  
Experimental Comparison ◽  
Abrasive Water Jet ◽  
Technological Parameters ◽  
Microsoft Excel ◽  
Frequency Spectra ◽  
Acceleration Amplitude ◽  
The Impact ◽  
The Given

Abrasive water jet technology is among the unconventional ways of machining. In today's modern and progressive era is often used for cutting and machining of various types of materials because of lower costs and environmental impact, as the cutting tool is water, in our case, with the addition of abrasives. Objective of the measurements was to evaluate the impact of vibration on the technological head in abrasive water jet technology in changing the selected technological parameters and the flow rate of technological head. In the given experiment, the used material - steel Hardox 500 with a thickness of 10 mm. The effort was to investigate the effects of changes in the speed rate of technological head (by speeds - 40, 200, 400 mm / min) on the size of the vibration acceleration amplitude and its frequency. Based on the measured values ​​of vibration to the technological head create the database and from it is evaluated the data in selected softwares (LabVIEW, SignalExpress and Microsoft Excel). Findings and conclusions are formulated on the basis of graphical dependencies, envelopes frequency spectra and comparison chart of envelopes.

Sign in / Sign up

Export Citation Format

Share Document