Fractal Characterization of Slurry Eroded Surfaces at Different Impact Angles

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Abouel-Kasem ◽  
M. A. Al-Bukhaiti ◽  
K. M. Emara ◽  
S. M. Ahmed
Keyword(s):  
Erosion Rate ◽  
Impact Angle ◽  
Oblique Impact ◽  
Slurry Erosion ◽  
Normal Impact ◽  
Power Spectral ◽  
Impact Angles ◽  
The Impact ◽  
The Relationship

In the present work, the topographical images of slurry erosion surfaces at different impact angles were quantified using fractal analysis. The study showed that the variation of fractal value of slope of linearized power spectral density with the impact angle is largely similar to the relationship between the erosion rate and the impact angle. Both the fractal value and erosion rate were maximum at 45 deg and 90 deg for ductile and brittle materials, respectively. It was found also that the variation of fractal values versus the impact angle has a general trend that does not depend on magnification factor. The fractal features to the eroded surfaces along different directions showed high directionality at oblique impact angle and were symmetrical at normal impact.

Stepwise Erosion as a Method for Investigating the Wear Mechanisms at Different Impact Angles in Slurry Erosion

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Y. M. Abd-Elrhman ◽  
A. Abouel-Kasem ◽  
S. M. Ahmed ◽  
K. M. Emara
Keyword(s):  
Rebound Effect ◽  
Impact Angle ◽  
Silica Sand ◽  
Slurry Erosion ◽  
Nominal Size ◽  
Erosion Mechanisms ◽  
Impact Angles ◽  
The Impact ◽  
Calculated Number ◽  
Number Of Particles

In the present work, stepwise erosion technique was carried out to investigate in detail the influence of impact angle on the erosion process of AISI 5117 steel. The number of impact sites and their morphologies at different impact angles were investigated using scanning electron microscope (SEM) examination and image analysis. The tests were carried out with particle concentration of 1 wt. %, and the impact velocity of slurry stream was 15 m/s. Silica sand—which has a nominal size range of 250–355 μm—was used as an erodent, using whirling-arm test rig. The results have shown that the number of craters, as expected, increases with the increase in the mass of erodent for all impact angles and this number decreases with the increase of the impact angle. In addition, the counted number of craters is larger than the calculated number of particles at any stage for all impact angles. This may be explained by the effect of the rebound effect of particles, the irregular shape for these particles, and particle fragmentation. The effect of impact angle based on the impact crater shape can be divided into two regions; the first region for θ ≤ 60 deg and the second region for θ ≥ 75 deg. The shape of the craters is related to the dominant erosion mechanisms of plowing and microcutting in the first region and indentation and lip extrusion in the second region. In the first region, the length of the tracks decreases with the increase of impact angle. The calculated size ranges are from few micrometers to 100 μm for the first region and to 50 μm in the second region. Chipping of the former impact sites by subsequent impact particles plays an important role in developing erosion.

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.

Shock Pressure in Oblique Impact—A Theoretical Analysis

1974 ◽  
Vol 41 (1) ◽  
pp. 124-130 ◽  
Author(s):  
C. A˚ke Persson
Keyword(s):  
Shock Wave ◽  
Pressure Rise ◽  
Impact Angle ◽  
Oblique Impact ◽  
Shock Pressure ◽  
Elastic Media ◽  
Linear Elastic ◽  
Wave Velocities ◽  
Impact Angles ◽  
The Impact

The variation of shock pressure with the angle between the colliding surfaces in an oblique impact between two plane plates is analyzed theoretically. The analysis is carried out for small impact angles and the plate materials are assumed to behave like fluids (Case 1) and linear elastic media (Case 2). In the latter case the two extreme assumptions concerning the friction at the interface, no friction and no sliding, are treated. The results show that the shock pressure increases quadratically with the impact angle (except for some of the no sliding cases, where decreasing pressure can occur) and that the pressure rise is strongly dependent upon the ratio between the impact velocity and the shock wave velocities for the plate materials.

scholarly journals Slurry Erosion–Corrosion Characteristics of As-Built Ti-6Al-4V Manufactured by Selective Laser Melting

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3967 ◽  
Author(s):  
Saleh Ahmed Aldahash ◽  
Osama Abdelaal ◽  
Yasser Abdelrhman
Keyword(s):  
Selective Laser Melting ◽  
Tap Water ◽  
Pure Water ◽  
Impact Angle ◽  
High Mass ◽  
Slurry Erosion ◽  
Laser Melting ◽  
Erosion Corrosion ◽  
Impact Angles ◽  
The Impact

Erosion and erosion–corrosion tests of as-built Ti-6Al-4V manufactured by Selective Laser Melting were investigated using slurries composed of SiO2 sand particles and either tap water (pure water) or 3.5% NaCl solution (artificial seawater). The microhardness value of selective laser melting (SLM)ed Ti-6Al-4V alloy increased as the impact angle increased. The synergistic effect of corrosion and erosion in seawater is always higher than erosion in pure water at all impact angles. The seawater environment caused the dissolution of vanadium oxide V2O5 on the surface of SLMed Ti-6Al-4V alloy due to the presence of Cl− ions in the seawater. These findings show lower microhardness values and high mass losses under the erosion–corrosion test compared to those under the erosion test at all impact angles.

scholarly journals Study on the Influence of Sand Erosion Process on the Wear and Damage of Heat-Treated U75V Rail Steel

2020 ◽  
Vol 143 (8) ◽  
Author(s):  
Kang Shu ◽  
Wen-Jian Wang ◽  
Enrico Meli ◽  
Hao-Hao Ding ◽  
Zhen-Yu Han ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Velocity ◽  
Erosion Rate ◽  
Rail Steel ◽  
Impact Angle ◽  
Sand Particle ◽  
Erosion Wear ◽  
Heat Treated ◽  
Impact Angles ◽  
The Impact

Abstract Usually, rail materials are exactly affected by the erosion of windblown sand in the desert environment. For this reason, the influence of impact angle, particle velocity, and particle size on the erosion wear behavior of the U75V heat-treated rail steel, a material frequently employed in Chinese railways, were studied in this work. The results showed that, with increasing impact angle, the erosion rate increased between 15 deg and 45 deg, decreased between 45 deg and 75 deg, and then increased again between 75 deg and 90 deg. The highest erosion rate occurred at about 45 deg. When the particle velocity increased, the erosion rate increased approximately in a quadratic way. As the sand particle size increased, the erosion rate presented a decreasing trend. During the initial stage of erosion, shear craters, indentation craters, and ploughing craters were the main surface damage features. The shear craters predominated at the impact angle of 45 deg whereas the indentation craters predominated at 90 deg. During the steady-state of erosion, the rail damage was mainly composed of craters, platelets, and cracks. Both the length and depth of craters increased almost linearly with increasing particle velocity, whereas the increased rate of length was significantly higher than that of depth. The length and depth of craters increased with increasing particle size at 90 deg, whereas only the length increased with increasing particle size at 45 deg. The microstructure evolution and the formation mechanism of platelet at low impact angles were different from those at high impact angles. Platelet formation was the main erosion wear mechanism.

Effect of Impact Angle on Slurry Erosion Behavior and Mechanisms of Carburized AISI 5117 Steel

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Y. M. Abd-Elrhman ◽  
A. Abouel-Kasem ◽  
K. M. Emara ◽  
S. M. Ahmed
Keyword(s):  
Erosion Resistance ◽  
Impact Angle ◽  
Silica Sand ◽  
Ductile Material ◽  
Hardness Profile ◽  
Slurry Erosion ◽  
Erosion Behavior ◽  
Nominal Size ◽  
Impact Angles ◽  
The Impact

The paper reports the influence of carburizing on the slurry erosion behavior of AISI 5117 steel using a whirling-arm rig. The microstructure and hardness profile of the surface layer of carburized steel were investigated. For characterizing the slurry damage process and for better understanding of material removal at different angles, scanning electron microscope (SEM) images at different locations on eroded surface using stepwise erosion combined with relocation SEM were presented. The study is also focused on studying the erosion wear resistance properties of AISI 5117 steel after carburizing at different impact angles. The tests were carried out with particle concentration of 1 wt. %, and the impact velocity of slurry stream was 15 m/s. Silica sand has a nominal size range of 250 – 355 μm was used as an erodent. The results showed that, carburizing process of steel increased the erosion resistance and hardness compared with untreated material for all impact angles. The erosion resistance of AISI 5117 steel increases by 75%, 61%, 33%, 10% at an impact angle of 30 deg, 45 deg, 60 deg, and 90 deg, respectively, as result of carburizing, i.e., the effectiveness of carburizing was the highest at low impact angles. Treated and untreated specimens behaved as ductile material, and the maximum mass loss appeared at impact angle of 45 deg. Plough grooves and cutting lips appeared for acute impact angle, but the material extrusions were for normal impact angles. The erosion traces were wider and deeper for untreated specimens comparing by the shallower and superficial ones for the carburized specimens. Chipping of the former impact sites by subsequent impact particles plays an important role in developing erosion.

REBOUND BEHAVIOUR OF SPHERES DURING ELASTIC-PLASTIC OBLIQUE IMPACTS

2008 ◽  
Vol 22 (09n11) ◽  
pp. 1095-1102 ◽  
Author(s):  
CHUAN-YU WU ◽  
COLIN THORNTON ◽  
LONG-YUAN LI
Keyword(s):  
Plastic Deformation ◽  
Permanent Deformation ◽  
Impact Angle ◽  
Plastic Substrate ◽  
Normal Impact ◽  
Elastic Substrate ◽  
Elastic Plastic ◽  
Oblique Impacts ◽  
Impact Angles ◽  
The Impact

In this paper, the influence of plastic deformation on the rebound behaviour of spheres during oblique impacts with a substrate at various impact angles is analysed using Finite Element Methods (FEM). Both oblique impacts of the elastic spheres with an elastic-plastic substrate and those of an elastic-plastic sphere with an elastic substrate are considered. For each impact case, impact angles ranging from 0° to 85° are specified by either keeping the impact speed constant, i.e, changing impact angle will vary both the normal impact velocities and tangential velocities, or keeping the normal impact velocity constant, i.e., only the tangential velocities are changed for different impact angles. It has been found that, during oblique impacts, the plastic deformation not only dissipates the initial impact kinetic energy but also leads to permanent deformation of the impacting bodies that significantly affect the rebound behaviour of the spheres, especially at relatively high impact angles. Consequently, the rebound behaviour of spheres during oblique impacts depends upon which of contacting bodies (the sphere or the substrate) deforms plastically and different rebound behaviours were observed between the impacts of an elastic sphere with an elastic-plastic substrate and those of an elastic-plastic spheres with an elastic substrate.

Research on Solid Particle Erosion Behaviors of TC4 Alloy at Different Erosion Angles

2014 ◽  
Vol 1049-1050 ◽  
pp. 167-170
Author(s):  
Bao Hui Guo
Keyword(s):  
Solid Particle ◽  
Erosion Rate ◽  
Impact Angle ◽  
Large Impact ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Erosion Mechanism ◽  
Tc4 Alloy ◽  
Impact Angles ◽  
The Impact

The solid particle erosion behaviors of TC4 Alloy were studied at different erosion angles. The results show that the erosion rate of TC4 alloy at impact angle 30o was higher than those at the impact angles of both 60o and 90o. At low impact angle, the erosion mechanism could be concluded as grinding erosion and furrow erosion. However, the erosion mechanism could be fatigue erosion at large impact angle.

Stress and System Energy in Erosion Process for Brittle Materials

2011 ◽  
Vol 239-242 ◽  
pp. 1165-1170
Author(s):  
Xiao Qing Lian ◽  
Xiu Mei Feng ◽  
Ming Xue Jiang
Keyword(s):  
Erosion Rate ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Target Material ◽  
Impact Angle ◽  
Erosion Process ◽  
Particle Erosion ◽  
System Energy ◽  
Impact Angles ◽  
The Impact

Erosion tests on high strengh refractory castables were carried out using SiC grains at impact angles of 30°,45°,60°,and 90° with the velocity of 5m/s.In order to study the variation in stress and system energy with impact angles during solid particle erosion process,a single particle erosion model was designed by means of three-dimensional explicit dynamic software ANSYS/LS-DYNA according to experiment parameters. The Johnson-Holmquist brittle ceramic model was employed to model the failure of target material. The impact angles varied from 15° to 90° in increments of 15°.The simulation results were compared with erosion rate values from experiments. The results show that the variation trends of both the maximum stress of targets and system total energy loss are in a good agreement with experiment data,which increaes with increasing impact angle. The variation of erosion rate as a function of impact angle can be explained by the variation of the maximum stress of target material. The rule “the maximum erosion of typical brittle material occurs at 90°” is confirmed by the view of energy analysis.

Research on characteristics of occupant’s chest responses in oblique impact

2021 ◽  
pp. 095440702110339
Author(s):  
Jindong Wu ◽  
Sen Xiao ◽  
Jingpu Hou ◽  
Zhiyue Liu ◽  
Xuewei Shi
Keyword(s):  
Traffic Accidents ◽  
Primary Source ◽  
Impact Angle ◽  
Oblique Impact ◽  
Peak Force ◽  
Chest Injury ◽  
Chest Injuries ◽  
Impact Angles ◽  
Serious Injuries ◽  
The Impact

The oblique impact is the second most common frontal impact, in which both the forward and lateral accelerations are applied to the occupant. It is noticed that the oblique impact is a primary source of serious injuries, in which the chest injuries are mostly fatal through the statistics of traffic accidents. This study aims to investigate the characteristics of the occupant’s chest injury in the frontal oblique impact. First, a model with a sled and a Test Human Occupant Restraint (THOR) dummy is established. Second, an acceleration curve with a peak of 9.0 g is applied to the sled. Then 11 sets of simulations with different impact angles and belt peak loads are conducted to evaluate the occupant’s chest responses. Results indicate that there is a negative correlation between belt peak force and injury outcomes, while there is a weak correlation between chest injury and impact angle. With the increase of the belt force limit, the chest deflection at Lower Left (LL) would increase by 37.9%, and the acceleration at LL would increase by 23.1%. Meanwhile, the Viscous Criterion (VC) at LL would increase by 61.4%. However, the relationship between the impact angle and injury drawn by VC and acceleration is inconsistent. Additionally, in all simulations, the maximum deflections are captured at the LL, while the maximum VCs happens at Upper Right (UR) or LL. It is demonstrated that a seatbelt with a lower peak force is friendly to the occupant’s chest under all the impact angles. This study can provide a reference to the study of chest injury in the oblique impact.

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