scholarly journals Simulating a high-speed abrasive particle impacting on a tensile block using SPH-FEM

2021 ◽  
Author(s):  
Yanjie Liu ◽  
Yue Zhao ◽  
Kenji Yoshigoe ◽  
Shijin Zhang ◽  
Ming Chen
Keyword(s):  
High Speed ◽  
Abrasive Particle

Research of the Dynamic Abrasive Particles Field

2009 ◽  
Vol 407-408 ◽  
pp. 569-572
Author(s):  
Shi Ming Ji ◽  
Ya Qi Shen ◽  
Li Zhang ◽  
Ming Sheng Jin ◽  
Yin Dong Zhang
Keyword(s):  
Image Processing ◽  
High Speed ◽  
Abrasive Particle ◽  
Critical Study ◽  
Abrasive Particles ◽  
Particle Field ◽  
Surface Polishing ◽  
Working Surface ◽  
Motion State ◽  
Dynamic Form

In this paper, a critical study into the dynamic form of abrasive particles through polishing are made, which are under “inconsistent curvature contact” status. In this system, some abrasive particles are colored up and mixed with ordinary ones, by utilizing transparent working surface and stroboscopic light as well; motion state of abrasive particles can be photographed by high speed shot technology. This method can get serials of images while polishing. By using digital image processing technology, distribution of abrasive particle field can be obtained finally. In this paper, the abrasive particles field is researched to obtain the perfect abrasive particle field after purposefully control. Then the influence of the removed material caused by abrasive particles field can be improved, so it can provide strong theory foundation and practice guidance to surface polishing practice.

scholarly journals Laser shadowgraphy measurement of abrasive particle mass, size and velocity distributions through micro-masks used in abrasive jet micro-machining

2021 ◽  
Author(s):  
Damon Dehnadfar
Keyword(s):  
Mass Flux ◽  
High Speed ◽  
Abrasive Particle ◽  
Particle Mass ◽  
Spherical Particles ◽  
Surface Evolution ◽  
Free Jets ◽  
Free Jet ◽  
Mass Size ◽  
First Time

In abrasive jet micromachining (AJM), a jet of particles is passed through narrow mask openings in order to define the features to be micro-machined. The size and shape of the micro-machined features depends on the distribution of the particle velocity and mass flux through the mask openings. In this work, a high speed laser shadowgraphy technique was used to demonstrate experimentally, for the first time, the significant effect of the mask opening size and powder shape and size on the resulting distribution of particle mass flux and velocity through the mask opening. In particular, it was found that the velocity through the mask was approximately constant, but different in magnitude than the velocity in the free jet incident to the mask. The measured mass flux distributions were in excellent agreement with a previously developed analytical model, thus directly confirming its validity. Additional measurements also showed that an existing numerical model could be used to predict the velocity distribution in free jets of spherical particles, and, if a modification to the particle drag coefficient is made, in free jets of angular particles. The direct experimental verification of these models allow for their use in surface evolution models that can predict the evolving shape of features micro-machined using AJM.

scholarly journals Simulating a High-speed Abrasive Particle Impacting on a Tensile Block Using SPH-FEM

2021 ◽  
Author(s):  
Yanjie Liu ◽  
Yue Zhao ◽  
Kenji Yoshigoe ◽  
Shijin Zhang ◽  
Ming Chen
Keyword(s):  
Material Property ◽  
High Speed ◽  
Abrasive Particle ◽  
Test Method ◽  
Abrasive Waterjet ◽  
Abrasive Particles ◽  
Erosion Damage ◽  
Particle Hydrodynamics ◽  
Orthogonal Test Method ◽  
Smoothed Particle

Abstract In recent years, more and more researches have been carried out on the erosion mechanism of abrasive particles on target materials in the abrasive waterjet cutting process. However, the effect of material property factors on the target erosion damage is rarely studied systematically. In this work, a 3D smoothed particle hydrodynamics-finite elements model is established for the simulation. The controlled variable method is used to study how each material property factor affects the erosion process of single abrasive particle and to find out the key material property factors of Al6061-T6 and Ti-6Al-4V. The influence of the interaction of the key material property factors on the target erosion damage is further evaluated using the orthogonal test method.

Prevention of Nozzle Wear in Abrasive Water Suspension Jets (AWSJ) Using Porous Lubricated Nozzles

2002 ◽  
Vol 125 (1) ◽  
pp. 168-180 ◽  
Author(s):  
Umang Anand ◽  
Joseph Katz
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Abrasive Particle ◽  
High Viscosity ◽  
Oil Viscosity ◽  
Axisymmetric Nozzle ◽  
Oil Film ◽  
Nozzle Wear ◽  
Dimensional Facility ◽  
The Impact

This paper introduces a novel method for preventing nozzle wear in abrasive water jets. It consists of using a porous nozzle, surrounded by a reservoir containing high-viscosity lubricant, which is exposed to the same driving pressure as the flow in the nozzle. The pressure difference across the porous medium, generated due to the high-speed flow in the nozzle, continuously forces lubricant through it. The resulting thin oil film forming on the walls of the nozzle protects the walls from the impact and shear caused by the abrasive particles. The porous nozzles were manufactured using Electric Discharge Machining and examined with Scanning Electron Microscopy. Two test facilities were used for evaluating the porous lubricated nozzles. The first was a two-dimensional facility, supporting a 145 μm wide nozzle with windows on both sides, which enabled visualization of the oil film and measurements of the liquid and abrasive-particle velocities using Particle Image Velocimetry. The measured slip velocities were also compared to computed values from a simple numerical model involving one-way coupling. The second facility used a 200 μm axisymmetric nozzle to determine the extent of nozzle wear under different conditions. We found that the presence of an oil film substantially reduced the extent of nozzle wear, from 111 percent of the diameter, when the nozzle was not lubricated, to 4 percent, when the oil viscosity was 1800 mm2/s and its flow rate was 2.4 percent of the water flow (over the same period). The wear increased as the lubricant flow rate and viscosity decreased. The presence of the oil film also improved the coherence of the jet.

scholarly journals Laser shadowgraphy measurement of abrasive particle mass, size and velocity distributions through micro-masks used in abrasive jet micro-machining

2021 ◽  
Author(s):  
Damon Dehnadfar
Keyword(s):  
Mass Flux ◽  
High Speed ◽  
Abrasive Particle ◽  
Particle Mass ◽  
Spherical Particles ◽  
Surface Evolution ◽  
Free Jets ◽  
Free Jet ◽  
Mass Size ◽  
First Time

In abrasive jet micromachining (AJM), a jet of particles is passed through narrow mask openings in order to define the features to be micro-machined. The size and shape of the micro-machined features depends on the distribution of the particle velocity and mass flux through the mask openings. In this work, a high speed laser shadowgraphy technique was used to demonstrate experimentally, for the first time, the significant effect of the mask opening size and powder shape and size on the resulting distribution of particle mass flux and velocity through the mask opening. In particular, it was found that the velocity through the mask was approximately constant, but different in magnitude than the velocity in the free jet incident to the mask. The measured mass flux distributions were in excellent agreement with a previously developed analytical model, thus directly confirming its validity. Additional measurements also showed that an existing numerical model could be used to predict the velocity distribution in free jets of spherical particles, and, if a modification to the particle drag coefficient is made, in free jets of angular particles. The direct experimental verification of these models allow for their use in surface evolution models that can predict the evolving shape of features micro-machined using AJM.

scholarly journals Effects of Abrasive Particle Type, Load and Sliding Distance on Micro-Abrasion Resistance of High Speed Steel Coated with AlCrN or AlTiN

2021 ◽  
Vol 27 (1) ◽  
pp. 50-56
Author(s):  
Vedat Veli ÇAY
Keyword(s):  
Physical Vapor Deposition ◽  
High Speed ◽  
Abrasive Particle ◽  
High Speed Steel ◽  
Wear Loss ◽  
Test Load ◽  
Abrasive Particles ◽  
Micro Grooving ◽  
Number Of Cycles ◽  
Wear Tests

High Speed Steel (HSS) specimen surfaces were coated with AlCrN and AlTiN via Physical Vapor Deposition (PVD) method. Then, the wear performances of the film coatings so produced were investigated by using different abrasive types with different particle sizes. During the micro-abrasion wear tests, 0.5, 1 and 1.5 N loads were applied for periods of 60 and 180 seconds. During the wear tests, wear loss increased with increasing SiC and Al2O3 abrasive particle size. Micro-grooving and micro-rolling wear were observed when F800 and F1200 abrasive slurry were used, respectively. It was determined that the volume losses formed by SiC abrasive particles on AlTiN and AlCrN coatings to be higher than Al2O3 abrasive particles. Volume losses increased with the increase in the applied load and the number of cycles. The AlCrN coatings exhibited better wear resistance than the AlTiN coatings. The applied test load had a significant effect on the wear mechanisms observed.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

The on-line use of histogram data for high-speed correction and alignment of electron microscope images

1984 ◽  
Vol 42 ◽  
pp. 556-557
Author(s):  
William Krakow
Keyword(s):  
Power Spectrum ◽  
High Speed ◽  
Direct Memory Access ◽  
Digital Television ◽  
Contrast Transfer Function ◽  
The Past ◽  
High Resolution Tem ◽  
On Line ◽  
Correction Of Astigmatism ◽  
The Fourier Transform

In the past few years on-line digital television frame store devices coupled to computers have been employed to attempt to measure the microscope parameters of defocus and astigmatism. The ultimate goal of such tasks is to fully adjust the operating parameters of the microscope and obtain an optimum image for viewing in terms of its information content. The initial approach to this problem, for high resolution TEM imaging, was to obtain the power spectrum from the Fourier transform of an image, find the contrast transfer function oscillation maxima, and subsequently correct the image. This technique requires a fast computer, a direct memory access device and even an array processor to accomplish these tasks on limited size arrays in a few seconds per image. It is not clear that the power spectrum could be used for more than defocus correction since the correction of astigmatism is a formidable problem of pattern recognition.

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