scholarly journals Applications of ceramics in composite protective structures

2021 ◽  
Vol 2 (396) ◽  
pp. 52-66
Author(s):  
A. Dulnev ◽  
Keyword(s):  
High Speed ◽  
Analytical Approach ◽  
High Efficiency ◽  
Experimental Studies ◽  
Ceramic Materials ◽  
Ship Structures ◽  
Collapse Simulation ◽  
Crystalline Ceramic ◽  
Protective Structures ◽  
The Impact

Object and purpose of research. The object of the study is ceramic-containing protective structures. The purpose of the study is to substantiate the feasibility and effectiveness of using ceramics as part of standard ship structures for protection against the effects of high-speed damaging elements. Materials and methods. Composites of the "ceramic + steel", "ceramic + fiberglass" type, made with the use of poly-crystalline ceramic materials based on boron carbide, nitride and silicon carbide, aluminum oxide and some other types, are considered. The study is based on an analytical approach, the results of ballistic tests of ceramic-containing composites and computational collapse simulation of ceramics in the composition of armor structures. Main results. The results of experimental studies demonstrating the level of efficiency of ceramic-containing structures are presented. The influence of the fragmentation features of various types of ceramics on the ballistic robustness of protective structures is shown. Structural and technological solutions aimed at increasing the survivability and ensuring the mounting of ceramic-containing structures on the ship are presented. Conclusion. The high efficiency of ceramics use in ship structures for protection against the impact of high-speed damaging elements is demonstrated. The use of ceramics in protective structures allows to get a significant increase in the ballistic robustness of structures while ensuring their ballistic survivability.

FEATURES OF HIGH-SPEED THE SUPER-FINISHING DISCS CERAMIC

2020 ◽  
pp. 3-9
Author(s):  
V. G. Yuriev ◽  
Yu. M. Zubarev
Keyword(s):  
High Speed ◽  
High Performance ◽  
Experimental Studies ◽  
Cutting Speed ◽  
Ceramic Materials ◽  
Processing Conditions ◽  
Duration Of Treatment ◽  
Metal Products ◽  
Stock Removal ◽  
The Impact

The possibility of providing high performance of super-finishing of ceramics based on the analysis of the processes of super-finishing of metal products is proved. For conducting experimental studies, a special installation has been developed, including a sharpening machine and a device for superfinishing. For such processing conditions, the necessity of using a low-rigidity technological system is justified. Discs made of ceramic materials of various machinability with diamond bars were super-finished at a cutting speed of up to 9.1 m/s and a clamping force of up to 90 N. Experimental data on the change in the value of cut allowance on the duration of treatment, the impact speed super-finishing of ceramic disks and grit sizes of diamond bars on the magnitude and rate of stock removal, roughness and waviness of machined surfaces and consumption of the tool. The results of super finishing of ceramic materials with processing of metal products are compared.

scholarly journals The Capabilities of Electrodischarge Microdrilling of High Aspect Ratio Holes in Ceramic Materials

2015 ◽  
Vol 6 (3) ◽  
pp. 61-69 ◽  
Author(s):  
Sebastian Skoczypiec ◽  
Magdalena Machno ◽  
Wojciech Bizoń
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Efficiency ◽  
Ceramic Materials ◽  
Good Alternative ◽  
Discharge Voltage ◽  
Drilling Speed ◽  
Electrically Conductive ◽  
Side Gap ◽  
The Impact

Abstract In the first part of the article the review of ceramic materials drilling possibilities was presented. Among the described methods special attention is paid to electrodischarge drilling. This process have especially been predicted for machining difficult-to-cut electrically conductive materials. The second part consist of the results analysis of electrodischarge microdrilling of siliconized silicon carbide. The experiment involves the impact of current amplitude, discharge voltage and pulse time on the hole depth, side gap, linear tool wear and mean drilling speed. The results shows that electrodischarge drilling is a good alternative when machining inhomogeneous ceramic materials and gives possibility to drill high aspect ratio holes with relatively high efficiency (the drilling speed >2 mm/min).

Investigation of Material Deformation by the High-Speed Water Slugs

2002 ◽  
Author(s):  
O. Petrenko ◽  
E. S. Geskin ◽  
G. A. Atanov ◽  
B. Goldenberg ◽  
A. Semko
Keyword(s):  
Shock Waves ◽  
Nozzle Exit ◽  
High Speed ◽  
Numerical Models ◽  
Water Pressure ◽  
Experimental Studies ◽  
Surface Cleaning ◽  
Water Velocity ◽  
Material Deformation ◽  
The Impact

Water constitutes an attractive manufacturing tool It is readily available and clean. The waterjets are conventionally used for surface cleaning, material removal, and surface modification. The intrinsic shortcomings of such an application are the need in the use of expensive and heavy pumping facilities and, what are more important, peculiarities of the waterjet-substrate interaction which limit material deformation by the incoming jet. These shortcomings are eliminated if the workpiece is impacted by the array of the water slugs, generated by the direct injection of high-intensity energy pulses into the water vessel (barrel) and ejection the portion of the water via the nozzle attached into the barrel. Such a device (barrel-nozzle combination) will constitute an effective and versatile manufacturing tool. Understanding of the phenomena that occur in the course of the energy injection into the water is necessary for the design of the desired device. The phenomena in question are determined by the ratio between the speed of the water in the barrel in the course of the energy injection and the speed of the shock waves in the water. If this ratio is much less than unity, the exit velocity is determined by the ratio between the cross section areas of the nozzle exit and the barrel. If the ratio in question approaches the unity, the water velocity at the nozzle exit is determined by the impact pressure. The device utilizing this principle is termed the water extruder. If however, the ratio is much more than unity the exit water velocity is determined by the superposition of shock waves developed in the fluid. This device termed the water cannon is able to accelerate the water slug to the speed far exceeding 1,000 m/sec. The numerical and experimental studies of water extruder were carried out. The numerical models were constructed and the variation of the water velocity and the water pressure in the barrel were investigated. Experimental setup for the study of the water extruder was constructed by the modification of Remington power tool. The experiments involved the piercing of metal strips. The effect of operational conditions on the maximal depth of the piecing was determined. Another series of experiments involved the study of the slug impact on plastic (lead) and brittle (concrete) materials. The effect of the stand off distance on the removal of both kinds of material was investigated. As the result the suggestions about the way of construction of the water extruders and their practical applications were made.

scholarly journals Modeling of the interaction of the layered barrier with a high-speed fragment

2019 ◽  
Vol 221 ◽  
pp. 01042
Author(s):  
Alexandr Ishchenko ◽  
Nikolay Belov ◽  
Viktor Burkin ◽  
Anton Sammel ◽  
Nikolay Yugov ◽  
...  
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Software Systems ◽  
Fracture Mechanisms ◽  
Elasticity Limit ◽  
Transparent Armor ◽  
Initial Stage ◽  
Numerical Research ◽  
Shock Wave Pressure ◽  
The Impact

For the manufacture of transparent armor of high class protection, as a rule, reinforced silicate glasses, as well as transparent ceramics, are used. Since these materials are resiliently brittle, they can be used only in transparent multilayered barriers with protective back films for protection against high-speed fragmentation elements and bullets. Plexiglass or polycarbonate is most often used as the back layer. The barrier’s face layer must have a hardness substantially higher than the hardness of the drummer’s material, and the Hugonievskii elasticity limit must exceed the shock-wave pressure arising at the initial stage in the barrier. The purpose of this paper is to develop a mathematical model that allows, within the framework of a porous elastic-plastic medium with regard to various fracture mechanisms, to calculate the impact interaction of fragmentation elements with transparent armor. Numerical research was conducted with the help of copyright software systems. Experimental studies of the collision of transparent armor with a splinter simulator in the speed range of 1500 ... 2500 m / s were carried out with the use of throwing installations of the NRI AMM TSU.

scholarly journals Particle–wall collisions in a viscous fluid

2001 ◽  
Vol 433 ◽  
pp. 329-346 ◽  
Author(s):  
G. G. JOSEPH ◽  
R. ZENIT ◽  
M. L. HUNT ◽  
A. M. ROSENWINKEL
Keyword(s):  
Reynolds Number ◽  
Viscous Fluid ◽  
High Speed ◽  
Particle Density ◽  
Particle Surface ◽  
Density Ratio ◽  
Experimental Studies ◽  
Stokes Number ◽  
Coefficient Of Restitution ◽  
The Impact

This paper presents experimental measurements of the approach and rebound of a particle colliding with a wall in a viscous fluid. The particle's trajectory was controlled by setting the initial inclination angle of a pendulum immersed in a fluid. The resulting collisions were monitored using a high-speed video camera. The diameters of the particles ranged from 3 to 12 mm, and the ratio of the particle density to fluid density varied from 1.2 to 7.8. The experiments were performed using a thick glass or Lucite wall with different mixtures of glycerol and water. With these parameters, the Reynolds number defined using the velocity just prior to impact ranged from 10 to approximately 3000. A coefficient of restitution was defined from the ratio of the velocity just prior to and after impact.The experiments clearly demonstrate that the rebound velocity depends on the impact Stokes number (defined from the Reynolds number and the density ratio) and weakly on the elastic properties of the material. Below a Stokes number of approximately 10, no rebound of the particle occurred. For impact Stokes number above 500 the coefficient of restitution appears to asymptote to the values for dry collisions. The coefficients of restitution were also compared with previous experimental studies. In addition, the approach of the particle to the wall indicated that the particle slowed prior to impacting the surface. The distance at which the particle's trajectory varied due to the presence of the wall was dependent on the impact Stokes number. The particle surface roughness was found to affect the repeatability of some measurements, especially for low impact velocities.

scholarly journals Investigating the Impact of Power-Take-Off System Parameters and Control Law on a Rotational Wave Energy Converter’s Peak-to-Average Power Ratio Reduction

2020 ◽  
Author(s):  
H. Bora Karayaka ◽  
Yi-Hsiang Yu ◽  
Nathan Tom ◽  
Eduard Muljadi
Keyword(s):  
Wave Energy ◽  
High Speed ◽  
High Efficiency ◽  
Average Power ◽  
Gear Ratio ◽  
Irregular Waves ◽  
Strong Impact ◽  
Power Ratio ◽  
Hardware In The Loop ◽  
The Impact

Abstract Due to the irregular nature of real waves, the power captured in a wave energy converter (WEC) system is highly variable. This is an important barrier to the effective use of WECs. To address this challenge, this study focuses on a rotational WEC power-take-off system in which high-speed and high-efficiency generators along with a torque/power smoothing inertia element can be effectively utilized. In the first phase of this study, the U.S. Department of Energy’s reference model 3 (WEC-Sim RM3; two-body point absorber), along with a slider-crank WEC, were integrated for linear to rotational conversion. Relative motion between the float and spar in RM3 was the driving force for this slider-crank WEC, which is connected to a motor/generator set through a gearbox. RM3 geometry was scaled down by 25 times to work within the limits of the physical motor/generator set used in the experimentation. Once the integration in a hardware-in-the-loop simulation environment was successfully completed, data on the peak-to-average power ratio was collected for various wave conditions including regular and irregular waves. The control algorithm designed to keep the system in resonance with waves was able to maintain relatively high speed depending on the specific gear ratio and wave period. Initial results with hardware-in-the-loop simulations reveal that gear ratio and crank radius have a strong impact on the peak-to-average power ratio. In addition, it was found that output power from the generator was maximized at a larger gear ratio, as the crank radius was increased.

Experimental Study on GMAW with Strip Electrode

2011 ◽  
Vol 314-316 ◽  
pp. 1025-1028
Author(s):  
Sen Mu Zheng ◽  
Hong Ming Gao
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Rectangular Cross Section ◽  
Strip Electrode ◽  
Welding Arc ◽  
Arc Pressure ◽  
Round Wire ◽  
The Impact ◽  
High Efficiency Welding ◽  
Welding System

GMAW with strip electrode is a new method, which uses the flat wire with a rectangular cross-section to replace the conventional round wire as consumable electrode. In the present study, the welding system was established. Then the typical arc behavior and metal transfer were analyzed. After that, high-speed-high-current welding experiment was carried out in both GMAW with strip electrode and conventional round wire. The results show that, Compared with the conventional GMAW with round wire, the welding arc of GMAW with strip electrode has much lower arc pressure, and the impact of the droplet on the weld pool is weakened remarkably. These two characteristics make GMAW with strip electrode suitable for high efficiency welding on the basis of maintaining the original advantages of GMAW.

scholarly journals Study of Y1Ba2Cu3O7−δ+CuO Nanocomposite as a Resistive Current Limiter

2019 ◽  
Vol 19 (02) ◽  
pp. 1950010 ◽  
Author(s):  
A. V. Ushakov ◽  
I. V. Karpov ◽  
V. G. Demin ◽  
A. A. Shaihadinov ◽  
A. I. Demchenko ◽  
...  
Keyword(s):  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
High Speed ◽  
High Efficiency ◽  
High Temperature Superconductors ◽  
Experimental Studies ◽  
Cuo Nanoparticles ◽  
Current Switch ◽  
Current Limiter

The influence of CuO nanoscale inclusions as the second component of the composites on the transport properties of superconducting polycrystals YBa2Cu3O7 was studied. Samples of YBa2Cu3O[Formula: see text] with different content of CuO nanoparticles were synthesized. The analysis of magnetic properties was carried out within the framework of the extended critical state model. It was found that the addition of 20[Formula: see text]wt.% CuO nanoparticles leads to an increase in the critical current density at [Formula: see text][Formula: see text]K. A further increase to 30[Formula: see text]wt.% reduces the critical current density. The results of the experimental studies of a switching superconducting fault current limiter in AC voltage networks based on high-temperature superconductors (HTSC) of the 2nd generation are given in this work. The testing equipment contains a series-connected HTSC module and a high-speed current switch with a break time of 9[Formula: see text]ms. The high efficiency of the samples made from the YBa2Cu3O[Formula: see text] + CuO nanocomposite material as an active element of a resistive current limiter is shown.

scholarly journals EXPERIMENTAL SUBSTANTIATION OF APPLICATION OZONIZED PHYSIOLOGICAL SOLUTION IN SURGICAL TREATMENT OF CHRONIC OSTEOMYELITIS

2016 ◽  
Vol 19 (3) ◽  
pp. 8-11
Author(s):  
I A Dotsenko ◽  
A K Chertkov ◽  
S N Skornyakov ◽  
B I Novikov ◽  
L A Golubeva
Keyword(s):  
Test Object ◽  
Culture Medium ◽  
High Efficiency ◽  
Saline Solution ◽  
Experimental Studies ◽  
The Body ◽  
Ozone Treatment ◽  
Experimental Conditions ◽  
Hematogenous Osteomyelitis ◽  
The Impact

Acute hematogenous osteomyelitis with inadequate treatment or no as such can become chronic. The latter involves a problem of not only increasing resistance of microorganisms to antibiotics (ABP), but their stable persistence in the body for a long time. Inability to achieve bactericidal concentrations of antibacterial drugs in the sequester due to lack of blood circulation in pyogenic foci makes inefficient traditional antimicrobial therapy. The purpose of this study - to justify the use of ozonated saline solution in the complex treatment of HGO through experimental research and development of optimal methods of influence on gram (+) and Gram (-) bacteria, fungi of the genus of Candida, Mycobacterium tuberculosis. We have carried out two series of experiments. To approximate the experimental conditions to the in vivo conditions of the surgical wound bacterial culture medium used - mylar fabric is hygroscopic and can largely mitigate the impact of aggressive antiseptic solutions to the CFU, simulating wall abscess (hereinafter referred to as the test object). One of a series of tubes with different concentrations of bacteria were exposed to ozonated saline with different exposures. The presence of colony growth test - bacteria on the test -object on the surface of the culture medium showed that ozone treatment for a given exposure time exposure did not provide a reliable germicidal effect. Lack of growth of colonies test - bacteria on test - and the object in a nutrient medium surface indicates the presence of bactericidal activity. The results of experimental studies have shown the high efficiency of ozonated saline against S. aureus ATCC 25923 with exposure 20 min., Ps. aeruginosa ATCC 27853 at 30 min exposure. In C. albicans strain 401 / 885-653 treatment ozonated saline solution has a bacteriostatic and pronounced inhibitory effect upon exposure of 30 minutes. This allows us to draw a conclusion on the appropriateness and effectiveness of the use of ozonated saline solution in the treatment of chronic hematogenous osteomyelitis of the spine.

The influence of aluminium, steel and polyurethane shoeing systems and of the unshod hoof on the injury risk of a horse kick

2017 ◽  
Vol 30 (05) ◽  
pp. 339-345 ◽  
Author(s):  
Miriam Sprick ◽  
Anton Fürst ◽  
Fabio Baschnagel ◽  
Silvain Michel ◽  
Gabor Piskoty ◽  
...  
Keyword(s):  
Contact Force ◽  
High Speed ◽  
Injury Risk ◽  
Experimental Studies ◽  
Soft Materials ◽  
Physical Parameters ◽  
Hard Materials ◽  
Probability Of Fracture ◽  
The Impact ◽  
Impact Duration

SummaryObjectives: To evaluate the damage inflicted by an unshod hoof and by the various horseshoe materials (steel, aluminium and polyurethane) on the long bones of horses after a simulated kick.Methods: Sixty-four equine radii and tibiae were evaluated using a drop impact test setup. An impactor with a steel, aluminium, polyurethane, or hoof horn head was dropped onto prepared bones. An impactor velocity of 8 m/s was initially used with all four materials and then testing was repeated with a velocity of 12 m/s with the polyurethane and hoof horn heads. The impact process was analysed using a high-speed camera, and physical parameters, including peak contact force and impact duration, were calculated.Results: At 8 m/s, the probability of a fracture was 75% for steel and 81% for aluminium, whereas polyurethane and hoof horn did not damage the bones. At 12 m/s, the probability of a fracture was 25% for polyurethane and 12.5% for hoof horn. The peak contact force and impact duration differed significantly between ‘hard materials’ (aluminium and steel) and ‘soft materials’ (polyurethane and hoof horn).Clinical significance: The observed bone injuries were similar to those seen in analogous experimental studies carried out previously and comparable to clinical fracture cases suggesting that the simulated kick was realistic. The probability of fracture was significantly higher for steel and aluminium than for polyurethane and hoof horn, which suggests that the horseshoe material has a significant influence on the risk of injury for humans or horses kicked by a horse.Supplementary Material for this article is available online at https://doi.org/10.3415/VCOT-17-01-0003ORCID iD MAJ: http://orcid.org/0000-0003-2142-2942

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