FEM Investigation of Phase Transformation in Vibration Assisted Nano Impact Machining by Loose Abrasives (VANILA)

2018 ◽  
Author(s):  
Nick H. Duong ◽  
J. Ma ◽  
Muhammad P. Jahan ◽  
Shuting Lei ◽  
Murali Sundaram
Keyword(s):  
Phase Transformation ◽  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Numerical Study ◽  
Impact Angle ◽  
Machining Parameters ◽  
Phase Volume ◽  
Impact Speed ◽  
Afm Probe ◽  
The Impact

In this paper, a numerical study of a nanomachining process, Vibration Assisted Nano Impact machining by Loose Abrasives (VANILA), has been conducted. In the VANILA process, an atomic force microscope (AFM) is used as a platform and the nano abrasives (diamond particles) are injected in slurry between the silicon workpiece and the vibrating AFM probe. The vibration of the AFM probe generates kinetic energy for the abrasives to impact the silicon workpiece and result in nanoscale material removal. In addition, silicon usually experiences phase transformation when subject to high pressure at nano-scale. The commercial Finite Element Method (FEM) software package Abaqus is employed to simulate the phase transformation experienced by the silicon workpiece in this VANILA process under different machining parameters such as impact speed, impact angle and coefficient of friction between the nano-abrasive and silicon workpiece. It is found that the machining parameters (impact speed, impact angle, and coefficient of friction) have substantial influence on the phase transformation of silicon workpiece in the nanomachining VANILA. Phase volumes for Si-VII, Si-VIII, and Si-X increase as the impact speed increases from 100 m/s to 200 m/s. Phase volume of Si-X increases as the friction coefficient increases. For Si-VII and Si-VIII, the phase volumes decrease as friction coefficient increases from 0.05, 0.3 and 0.5. In addition, the phase volumes for Si-VII, Si-VIII, and Si-X usually increase as the impact angles increases from 20° to 90°. However, for impact speed of 150 m/s and frictional coefficient of 0.05, the Si-VII phase volume increases first as impact angle increases from 20° to 70° and then decreases as the impact angle increases from 70° to 90°.

Numerical Investigation of Effect of Operating Parameters on the Phase Transformation During Vibration-Assisted Nano-Impact Machining of Silicon by Loose Abrasives

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Nick H. Duong ◽  
Jianfeng Ma ◽  
Muhammad P. Jahan ◽  
Shuting Lei ◽  
Vamshi Krishna Kore ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Friction Coefficient ◽  
Impact Angle ◽  
Transformation Process ◽  
Impact Speed ◽  
Atomic Force ◽  
Afm Probe ◽  
Linear Regression Modeling ◽  
Impact Angles ◽  
The Relationship

Abstract Vibration-assisted nano-impact machining by loose abrasives (VANILA) is a newly developed process based on the atomic force microscope (AFM) platform, where the nanoabrasive (diamond particles) slurry is injected between the workpiece and the vibrating AFM probe. This study aims to use the commercial finite element method (FEM) software package abaqus to simulate the phase transformation experienced by the silicon workpiece and to study the effects of VANILA process parameters, such as impact speed, impact angle, and coefficient of friction between the nanoabrasive and silicon workpiece, on the volume of phase transformation of silicon. Among these three parameters, impact speed is found to have the most dominating effect on the phase transformation process, followed by impact angle and friction coefficient. It is found that the volumes for Si-VII, Si-VIII, and Si-X phases increase with the increase of impact speed from 100 m/s to 200 m/s. The phase volumes of Si-VII and Si-VIII are found to decrease slightly with the increase of friction coefficient from 0.05 to 0.5. The phase volumes for Si-VII, Si-VIII, and Si-X are found to increase with the increase of impact angles from 20 deg to 90 deg. Finally, the multiple linear regression modeling using a design of experiments is carried out to study the relationship among the three parameters and the volume of different phases of silicon.

Numerical Investigation of the Damage Evolution in Vibration Assisted Nano Impact Machining by Loose Abrasives With Different Operating Parameters

2018 ◽  
Author(s):  
Nick H. Duong ◽  
J. Ma ◽  
Shuting Lei
Keyword(s):  
Material Removal ◽  
Frictional Coefficient ◽  
Material Model ◽  
Impact Angle ◽  
Ductile Material ◽  
Nanoscale Material ◽  
Impact Speed ◽  
Atomic Force ◽  
Afm Probe ◽  
The Impact

In this paper, the commercial FEM software package Abaqus is employed to model a novel nanomachining process, in which an atomic force microscope (AFM) is used as a platform and the nano abrasives injected in slurry between the workpiece and the vibrating AFM probe impact the workpiece and result in nanoscale material removal. Diamond particles are used as loose abrasives. The ductile material model is used to describe the behavior of the silicon workpiece. The effects of impact speed, impact angle, and the frictional coefficient between the workpiece and abrasives on material removal mechanism are investigated. It is found that the impact speed, impact angle, and frictional coefficient between the silicon workpiece and nanoabrasives have big influence on material removal volume in this novel nanomachining process.

FEM Investigation of the Effects of Impact Speed and Angle of Impacts of Abrasive in the Vibration Assisted Nano Impact Machining by Loose Abrasives

2017 ◽  
Author(s):  
Nick H. Duong ◽  
J. Ma ◽  
Shuting Lei
Keyword(s):  
Frictional Coefficient ◽  
Impact Angle ◽  
The Novel ◽  
Abrasive Machining ◽  
Nanoscale Material ◽  
Impact Speed ◽  
Atomic Force ◽  
Hard And Brittle Materials ◽  
Afm Probe ◽  
The Impact

In this paper, the commercial FEM software package Abaqus is employed to model the novel nanomachining process, Vibration Assisted Nano Impact machining by Loose Abrasives (VANILA), which combines the principles of vibration-assisted abrasive machining and tip-based nanomachining to conduct nano abrasive machining of hard and brittle materials. In this novel nanomachining process, an atomic force microscope (AFM) is used as a platform and the nano abrasives injected in slurry between the workpiece and the vibrating AFM probe impact the workpiece and result in nanoscale material removal. Diamond particles are used as the loose abrasives. The effects of impact speed, angle of impacts, and the frictional coefficient between the workpiece and abrasives are investigated using Abaqus. It is found that the impact speed, impact angle, and frictional coefficient between the silicon workpiece and nanoabrasives have big influence on the nanocavity’s size and depth.

scholarly journals A New Method for Predicting Erosion Damage of Suddenly Contracted Pipe Impacted by Particle Cluster via CFD-DEM

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1858 ◽  
Author(s):  
Jiarui Cheng ◽  
Yihua Dou ◽  
Ningsheng Zhang ◽  
Zhen Li ◽  
Zhiguo Wang
Keyword(s):  
Erosion Rate ◽  
Numerical Study ◽  
Target Surface ◽  
Impact Angle ◽  
Particle Collision ◽  
Particle Cluster ◽  
Interparticle Collision ◽  
Velocity Decay ◽  
Discrete Element Methods ◽  
The Impact

A numerical study on the erosion of particle clusters in an abrupt pipe was conducted by means of the combined computational fluid dynamics (CFD) and discrete element methods (DEM). Furthermore, a particle-wall extrusion model and a criterion for judging particle collision interference were developed to classify and calculate the erosion rate caused by different interparticle collision mechanisms in a cluster. Meanwhile, a full-scale pipe flow experiment was conducted to confirm the effect of a particle cluster on the erosion rate and to verify the calculated results. The reducing wall was made of super 13Cr stainless steel materials and the round ceramsite as an impact particle was 0.65 mm in diameter and 1850 kg/m3 in density. The results included an erosion depth, particle-wall contact parameters, and a velocity decay rate of colliding particles along the radial direction at the target surface. Subsequently, the effect of interparticle collision mechanisms on particle cluster erosion was discussed. The calculated results demonstrate that collision interference between particles during one cluster impact was more likely to appear on the surface with large particle impact angles. This collision process between the rebounded particles and the following particles not only consumed the kinetic energy but also changed the impact angle of the following particles.

Effect of Deterministic Asperity Geometry on Hydrodynamic Lubrication

2004 ◽  
Vol 126 (3) ◽  
pp. 527-534 ◽  
Author(s):  
Ravinder B. Siripuram ◽  
Lyndon S. Stephens
Keyword(s):  
Friction Coefficient ◽  
Cross Sections ◽  
Numerical Study ◽  
Hydrodynamic Lubrication ◽  
Leakage Rate ◽  
Area Fraction ◽  
Cross Sectional ◽  
Constant Height ◽  
Sectional Shape ◽  
The Impact

This paper presents a numerical study of the effects of different shapes of deterministic microasperities in sliding surface lubrication when hydrodynamic films are found. Positive (protruding) and negative (recessed) asperities of constant height (depth) are considered with circular, square, diamond, hexagonal and triangular cross-sections. Of particular interest is the impact of asperity/cavity cross-sectional geometry on friction and leakage, which has importance in sealing applications. The results indicate that the friction coefficient is insensitive to asperity/cavity shape, but quite sensitive to the size of the cross-section. By contrast, leakage rates are found to be quite sensitive to both cross-sectional shape and size, with triangular asperities giving the smallest leakage rate and square asperities giving a largest leakage rate. The minimum coefficient of friction for all shapes is found to occur at an asperity area fraction of 0.2 for positive asperities and 0.7 for negative asperities. Finally, the results indicate the existence of a critical asperity area fraction where the performance curves for positive and negative asperities cross over. These cross-over points are identified for friction coefficient and leakage rate.

A study on the frontal oblique collision-induced derailment mechanism in subway vehicles

2019 ◽  
Vol 234 (6) ◽  
pp. 584-595
Author(s):  
Shuguang Yao ◽  
Huifen Zhu ◽  
Mingyang Liu ◽  
Zhixiang Li ◽  
Ping Xu ◽  
...  
Keyword(s):  
Lateral Displacement ◽  
Element Model ◽  
Vertical Displacement ◽  
Rigid Wall ◽  
Impact Angle ◽  
Oblique Impact ◽  
Oblique Collision ◽  
Impact Speed ◽  
Vertical Displacements ◽  
The Impact

Oblique collisions can more easily lead to train derailment and cause heavy casualties. In this paper, a fine finite-element model of a subway head vehicle–rigid wall frontal oblique collision was established and validated by a single wheelset derailment simulation. Furthermore, the derailment mechanisms and patterns under an oblique impact angle of 6.34°–40° and at an impact speed of 8–40 km/h were studied via simulation. The results indicated that three types of derailment, such as roll-over derailment, climb/roll-over derailment and wheel-lift derailment, have occurred. When the impact speed was set to 25 km/h, a climb/roll-over derailment occurred under the impact angle of greater than 40°; a roll-over derailment occurred under the impact angle of 20°–40°; and the vehicle would not derail when the impact angle was less than 15°. When the impact angle was 6.34°, the vehicle was in danger of wheel-lift derailment with the largest wheel vertical displacement of 26.83 mm and lateral displacement of 12.52 mm under the impact speed of 40 km/h, but it was safe with the largest displacement of no more than 18 mm and lateral displacement of 8.39 mm if the impact speed was less than 40 km/h. It is shown that the derailment patterns are more sensitive to the impact angle. Therefore, both the lateral and vertical displacements should be considered when studying the oblique collision-induced derailment mechanisms and patterns.

scholarly journals Neck Moment Characterization of Restrained Child Occupant at Realistic Nontest Standard Higher Impact Speed of 32.2 km/h

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
S. Shasthri ◽  
V. Kausalyah ◽  
Qasim H. Shah ◽  
Kassim A. Abdullah ◽  
Moumen M. Idres ◽  
...  
Keyword(s):  
Interactive Effect ◽  
Impact Angle ◽  
Side Impact ◽  
Impact Speed ◽  
Child Restraint ◽  
Child Restraint System ◽  
Impact Angles ◽  
Child Occupant ◽  
The Impact

The effects of bullet vehicle crash impact angle, child restraint system design, and restraint harness slack at side impact speed of 32.2 km/h (20 mph) on moments sustained at the neck by a three-year-old child are investigated. Mathematical models are built using the response surface method based on simulation results whereby good fitness is achieved. The singular and cross interactive effect of each predictor on the neck moment are analyzed. The number of significant parameters affecting the neck moment is shown to be the largest for wide impact angles (ϕ≥60°) and the impact angle parameter is largely revealed to be the most sensitive. An ideal safe range for low neck moment has been established to be within ϕ angles 45° and 65°. It is further shown that the nature of all parameters effect on the neck moment is highly dependent on the impact angle range.

Assessment of NCHRP Report 350 Test Conditions

2002 ◽  
Vol 1797 (1) ◽  
pp. 38-43 ◽  
Author(s):  
King K. Mak ◽  
Roger P. Bligh
Keyword(s):  
Policy Decision ◽  
Impact Angle ◽  
Impact Speed ◽  
Current Test ◽  
Test Conditions ◽  
Level 3 ◽  
Current Impact ◽  
Areas Of Interest ◽  
The Impact ◽  
Test Impact

The appropriateness of test conditions specified in NCHRP Report 350 was assessed. The assessment focused on the basic Test Level 3 and addressed two areas of interest: the effects of higher speed limit on impact speed and the appropriateness of 25° for the impact angle. The following conclusions and recommendations were drawn on the basis of the results of the analysis: ( a) the current test impact speed of 100 km/h (62.2 mph) should be maintained, ( b) the current impact angle of 25° for Test 11 of length-of-need sections of permanent longitudinal barriers should be maintained, ( c) the test impact angle should be reduced from 25° to 20° for Test 11 of length-of-need sections of temporary longitudinal barriers, and ( d) the test impact angle should be reduced from 25° to 20° for Test 21 of barrier transition sections. However, the selection of impact conditions is more a policy decision than a technical issue to be resolved in the update of NCHRP Report 350 guidelines.

scholarly journals Numerical Study of the Interaction between Level Ice and Wind Turbine Tower for Estimation of Ice Crushing Loads on Structure

2019 ◽  
Vol 7 (12) ◽  
pp. 439 ◽  
Author(s):  
Ming Song ◽  
Wei Shi ◽  
Zhengru Ren ◽  
Li Zhou
Keyword(s):  
Numerical Simulations ◽  
Wind Turbine ◽  
Numerical Study ◽  
Mesh Size ◽  
Impact Speed ◽  
Wind Turbine Tower ◽  
Comparison Results ◽  
Ice Loads ◽  
Level Ice ◽  
The Impact

In this paper, the interaction between level ice and wind turbine tower is simulated by the explicit nonlinear code LS-DYNA. The isotropic elasto-plastic material model is used for the level ice, in which ice crushing failure is considered. The effects of ice mesh size and ice failure strain on ice forces are investigated. The results indicate that these parameters have a significant effect on the ice crushing loads. To validate and benchmark the numerical simulations, experimental data on level ice-wind turbine tower interactions are used. First, the failure strains of the ice models with different mesh sizes are calibrated using the measured maximum ice force from one test. Next, the calibrated ice models with different mesh sizes are applied for other tests, and the simulated results are compared to corresponding model test data. The effects of the impact speed and the size of wind turbine tower on the comparison between the simulated and measured results are studied. The comparison results show that the numerical simulations can capture the trend of the ice loads with the impact speed and the size of wind turbine tower. When a mesh size of ice model is 1.5 times the ice thickness, the simulations can give more accurate estimations in terms of maximum ice loads for all tests, i.e., good agreement between the simulated and measured results is achieved.

ASSESSMENT OF THE INFLUENCE OF THE COEFFICIENT OF FRICTION ON THE TEMPERATURE DISTRIBUTION OF A DISC BRAKE DURING THE BRAKING PROCESS

Tribologia ◽  
2019 ◽  
Vol 288 (6) ◽  
pp. 95-99
Author(s):  
Piotr Sokolski ◽  
Justyna Sokolska
Keyword(s):  
Temperature Distribution ◽  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Disc Brake ◽  
Thermal Processes ◽  
Reliable Operation ◽  
Similar Nature ◽  
The Coefficient Of Friction ◽  
Braking Process ◽  
The Impact

Brake assemblies are key mechanisms in the aspect of safe and reliable operation of devices and machines. Due to intense thermal processes that occur during braking, the brakes are exposed to an accelerated wear. The article assesses the impact of tribological cooperation conditions between the caliper and the disc of a disc brake on the temperature of a disc. The variable value in the simulations was the coefficient of friction between the cooperating surfaces. A direct effect of the increase of the analysed parameter on the enhancement of brake elements’ temperature was found. At the same time, a similar nature of thermal processes was observed for all values of the friction coefficient taken into account.

Sign in / Sign up

Export Citation Format

Share Document