Effect of Particle Impact Velocity on Cone Crack Shape in Ceramic Material

2005 ◽  
Vol 297-300 ◽  
pp. 1321-1326 ◽  
Author(s):  
Sang Yeob Oh ◽  
Hyung Seop Shin
Keyword(s):  
Impact Velocity ◽  
Computational Simulation ◽  
Back Surface ◽  
Particle Impact ◽  
Cone Crack ◽  
Crack Shape ◽  
The Impact ◽  
Particle Impact Velocity ◽  
Sic Particle ◽  
Ring Cracks

The damage behaviors induced in a SiC by a spherical particle impact having a different material and size were investigated. Especially, the influence of the impact velocity of a particle on the cone crack shape developed was mainly discussed. The damage induced by a particle impact was different depending on the material and the size of a particle. The ring cracks on the surface of the specimen were multiplied by increasing the impact velocity of a particle. The steel particle impact produced the larger ring cracks than that of the SiC particle. In the case of the high velocity impact of the SiC particle, the radial cracks were generated due to the inelastic deformation at the impact site. In the case of the larger particle impact, the morphology of the damages developed were similar to the case of the smaller particle one, but a percussion cone was formed from the back surface of the specimen when the impact velocity exceeded a critical value. The zenithal angle of the cone cracks developed into the SiC decreased monotonically as the particle impact velocity increased. The size and material of a particle influenced more or less on the extent of the cone crack shape. An empirical equation was obtained as a function of impact velocity of the particle, based on the quasi-static zenithal angle of the cone crack. This equation will be helpful to the computational simulation of the residual strength in ceramic components damaged by the particle impact.

scholarly journals Study on performance degradation and damage modes of thin-film photovoltaic cell subjected to particle impact

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kailu Xiao ◽  
Xianqian Wu ◽  
Xuan Song ◽  
Jianhua Yuan ◽  
Wenyu Bai ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Conversion Efficiency ◽  
Photovoltaic Cell ◽  
Performance Degradation ◽  
Particle Impact ◽  
Laser Shock ◽  
Number Density ◽  
Mechanical Modeling ◽  
The Impact ◽  
Impact Experiments

AbstractIt has been a key issue for photovoltaic (PV) cells to survive under mechanical impacts by tiny dust. In this paper, the performance degradation and the damage behavior of PV cells subjected to massive dust impact are investigated using laser-shock driven particle impact experiments and mechanical modeling. The results show that the light-electricity conversion efficiency of the PV cells decreases with increasing the impact velocity and the particles’ number density. It drops from 26.7 to 3.9% with increasing the impact velocity from 40 to 185 m/s and the particles’ number densities from 35 to 150/mm2, showing a reduction up to 85.7% when being compared with the intact ones with the light-electricity conversion efficiency of 27.2%. A damage-induced conversion efficiency degradation (DCED) model is developed and validated by experiments, providing an effective method in predicting the performance degradation of PV cells under various dust impact conditions. Moreover, three damage modes, including damaged conducting grid lines, fractured PV cell surfaces, and the bending effects after impact are observed, and the corresponding strength of each mode is quantified by different mechanical theories.

Numerical Investigation of Hammer Erosive Wear due to Particle Impact

2016 ◽  
Vol 846 ◽  
pp. 237-244 ◽  
Author(s):  
Md Shahanur Hasan ◽  
Dennis V. de Pellegrin ◽  
Douglas Hargreaves ◽  
Richard Clegg
Keyword(s):  
Coal Particle ◽  
High Speed ◽  
Computational Simulation ◽  
Particle Impact ◽  
Erosion Wear ◽  
Material Loss ◽  
Premature Failure ◽  
Solid Coal ◽  
Coal Particles ◽  
The Impact

Hammers are the key machine element of high-speed hammer mills which lead to the coal pulverisation process. Progressive material loss from the hammer occurs due to the mechanical interactions between the coal particles and the hammer surface. Coal pulveriser industries implement extensive efforts to combat against premature material loss from the hammer surface due to coal particle impact which may result in premature failure. This work investigates the erosion wear mechanism through computational simulation. A numerical model is developed using Abaqus® to simulate the solid coal particle impacting onto the hammer (target).The Abaqus/Explicit® dynamic simulation solver is used for this analysis. The interactions between the solid coal particles and the target are modelled using the Abaqus/Explicit® element deletion method. The Johnson and Cook plasticity model is employed to analyse the flow stress behaviour of ductile materials during impact. The developed stress and plastic strain are analysed through simulation on the impact surface. This model is applied to different ductile alloys to determine the best erosion wear resistance hammer material for extending the operating life of hammers in the coal pulverisation process.

Experimental Investigation of the Location of Maximum Erosive Wear Damage in Elbows

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Quamrul H. Mazumder ◽  
Siamack A. Shirazi ◽  
Brenton McLaury
Keyword(s):  
Experimental Investigation ◽  
Mass Loss ◽  
Solid Particle ◽  
Impact Velocity ◽  
Single Phase ◽  
Erosive Wear ◽  
Particle Impact ◽  
Erosion Behavior ◽  
Wear Damage ◽  
Particle Impact Velocity

Erosive wear damage of elbows due to solid particle impact has been recognized as a significant problem in several fluid handling industries. Solid particle erosion is a complex phenomenon due to different parameters causing material removal from the metal surface. The particle density, size, shape, velocity, concentration, impact angle, and impacting surface material properties are some of the major parameters. Among the various factors, the particle impact velocity has the greatest influence in erosion. The particle impact velocity and impact angles depend on the fluid velocity and fluid properties. The particle to particle, particle to fluid, and particle to wall interactions increase the complexity of the erosive wear behavior. In multiphase flow, the presence of different fluids and their corresponding spatial distribution of the phases, adds another dimension to the problem. Most of the previous investigations were focused on determination of erosion in terms of mass loss of the eroding surfaces without identifying the specific location of the maximum erosive wear. During this investigation, magnitude of erosion at different location of an elbow specimen was measured to determine the location of maximum erosion. Experimental investigation of erosion in single-phase and multiphase flows was conducted at different fluid velocities. Both mass loss and thickness loss measurements were taken to characterize erosion behavior and erosion patterns in an elbow. Experimental results showed different erosion behavior and location of maximum erosion damage in single-phase and multiphase flows. The locations of maximum wear due to erosion were also different for horizontal flow compared to vertical flow.

A Numerical Investigation Into Cold Spray Bonding Processes

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
Baran Yildirim ◽  
Hirotaka Fukanuma ◽  
Teiichi Ando ◽  
Andrew Gouldstone ◽  
Sinan Müftü
Keyword(s):  
Critical Velocity ◽  
Impact Velocity ◽  
Cold Spray ◽  
Cohesive Strength ◽  
Interfacial Bonding ◽  
Bonding Energy ◽  
Strength Parameter ◽  
Particle Impact ◽  
Particle Bonding ◽  
The Impact

Specific mechanisms underlying the critical velocity in cold gas particle spray applications are still being discussed, mainly due to limited access to in situ experimental observation and the complexity of modeling the particle impact process. In this work, particle bonding in the cold spray (CS) process was investigated by the finite element (FE) method. An effective interfacial cohesive strength parameter was defined in the particle–substrate contact regions. Impact of four different metals was simulated, using a range of impact velocities and varying the effective cohesive strength values. Deformation patterns of the particle and the substrate were characterized. It was shown that the use of interfacial cohesive strength leads to a critical particle impact velocity that demarcates a boundary between rebounding and bonding type responses of the system. Such critical bonding velocities were predicted for different interfacial cohesive strength values, suggesting that the bonding strength in particle–substrate interfaces could span a range that depends on the surface conditions of the particle and the substrate. It was also predicted that the quality of the particle bonding could be increased if the impact velocity exceeds the critical velocity. A method to predict a lower bound for the interfacial bonding energy was also presented. It was shown that the interfacial bonding energy for the different materials considered would have to be at least on the order of 10–60 J/m2 for cohesion to take place. The general methodology presented in this work can be extended to investigate various materials and impact conditions.

Particle Velocity Measurements to Improve Erosion Prediction

Volume 3 ◽  
2004 ◽  
Author(s):  
Matthew J. Sampson ◽  
Siamack A. Shirazi ◽  
Brenton S. McLaury
Keyword(s):  
Impact Velocity ◽  
Particle Velocity ◽  
Particle Interaction ◽  
Particle Impact ◽  
Average Particle ◽  
Rotating Disks ◽  
Erosion Testing ◽  
Erosion Prediction ◽  
Particle Velocities ◽  
Particle Impact Velocity

Previous work on Computational Fluid Dynamics (CFD) based erosion modeling indicated a strong influence of particle impact velocity on erosion. Equations to predict erosion are based on particle impacting velocity, material properties and particle characteristics such as particle shape and size. Previous studies did not measure particle velocity directly but used rotating disks or simplified computer models to determine the particle velocity. In the present work, a series of experiments have been conducted to measure the velocity of small particles (sand and aluminum) as they approach a target. A laser Doppler velocimetry system was used to measure particle velocities in a jet of air as the jet impinges a target. The angle between the target and the incoming jet is varied. Particle concentration is also controlled, allowing the effects of particle to particle interaction on average particle impact velocity to be observed. These findings are expected to improve the results of erosion testing and provide new data for improving erosion models.

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