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 STUDY OF THE TRANSPARENT ARMOR STRENGTH UNDER A HIGH-SPEED IMPACT OF A CYLINDRICAL IMPACTOR BY COMPUTER MODELING METHOD

2020 ◽  
pp. 69-77
Author(s):  
Nikolay N. BELOV ◽  
◽  
Nikolay T. YUGOV ◽  
Anton Yu. SAMMEL ◽  
Evgeniy Yu. STEPANOV ◽  
...  
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Advanced Materials ◽  
Polycrystalline Materials ◽  
Software Systems ◽  
Tempered Glass ◽  
High Speed Impact ◽  
Transparent Armor ◽  
Threat Level ◽  
The Impact

When manufacturing transparent multilayer armor of high threat level, the reinforced silicate glass and transparent ceramics with protecting back films are usually used. The hardness of the front layer of the shield should be much higher than that of the impactor. A promising option isthe use of a single leucosapphire crystal. However, due to its high cost and the impossibility of providing large-sized samples, the transparent polycrystalline materials are developed. One of the most advanced materials is ALON, which is close to leucosapphire in strength characteristics. The aim of this work is to develop a mathematical model to calculate the impact interaction of fragmentation elements with transparent armor. The numerical study is carried out using proprietary software systems. Calculations of the high-speed impact of the steel cylindrical impactor are implemented for three types of shields made of transparent armor. The first two-layer target is made of 20 mm thick tempered glass and a 4 mm thick polycarbonate layer. The second and third targets are three-layered. The front layer of the second target is made of ALON, and the spinel is used for the third one. The second and third layers in these targets are made of tempered glass and polycarbonate, respectively. The calculated results show that ALON is the most impact-resistant material, while spinel is a little less resistant.

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.

Reliability and Performance Analysis of Architecture-Based Software Implementing Restarts and Retries Subject to Correlated Component Failures

2015 ◽  
Vol 25 (08) ◽  
pp. 1307-1334 ◽  
Author(s):  
Xiao-Dan Li ◽  
Yong-Feng Yin ◽  
Lance Fiondella
Keyword(s):  
Software Reliability ◽  
High Reliability ◽  
Experimental Studies ◽  
Software Systems ◽  
Fault Recovery ◽  
Recovery Mechanism ◽  
Software Models ◽  
And Performance ◽  
Component Failures ◽  
The Impact

High reliability and performance are essential attributes of software systems designed for critical real-time applications. To improve the reliability and performance of software, many systems incorporate some form of fault recovery mechanism. However, contemporary models of software reliability and performance rarely consider these fault recovery mechanisms. Another notable shortcoming of many software models is that they make the simplifying assumption that component failures are statistically independent, which disagrees with several experimental studies that have shown that the failures of software components can exhibit correlation. This paper presents an architecture-based model of software reliability and performance that explicitly considers a two-stage fault recovery mechanism implementing component restarts and application-level retries. The application architecture is characterized by a Discrete Time Markov Chain (DTMC) to represent the dynamic branching behavior of control between the components of the application. Correlations between the component failures are computed with an efficient numerical algorithm for a multivariate Bernoulli (MVB) distribution. We illustrate the utility of the model through a case study of an embedded software application. The results suggest that the model can be used to quantify the impact of software fault recovery and correlated component failures on application reliability and performance.

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.

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 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.

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

Experimental Studies on Cutting Temperature of Nickel-Based Supper Alloy Inconel 718

2013 ◽  
Vol 584 ◽  
pp. 20-23
Author(s):  
Mao Hua Xiao ◽  
Ning He ◽  
Liang Li ◽  
Xiu Qing Fu
Keyword(s):  
Inconel 718 ◽  
High Speed ◽  
Experimental Studies ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Depth Of Cut ◽  
High Speed Milling ◽  
Radial Depth ◽  
The Impact

The method to measure the cutting speed when high speed milling nickel alloy Inconel 718 based on semi-artificial thermocouple. The cutting parameters, tool wear and so on the cutting temperature were analyzed. The tests showed that the temperature was gradually increased with the increase of cutting speed. The cutting speed must be more than 600m/min, when the ceramic tools would perform better cutting performance in the high-speed milling nickel-based superalloy. In order to achieve more efficient machining, milling speed can be increased to more than 1000m/min. The impact amount of Radial depth of cut and feed per tooth were relatively small.

Time Evolutions of Water Drops Impacting on a Rotating Disk

2011 ◽  
Vol 354-355 ◽  
pp. 609-614
Author(s):  
Jing Yin Li ◽  
Xiao Fang Yuan ◽  
Qiang Han
Keyword(s):  
High Speed ◽  
Water Drop ◽  
Experimental Studies ◽  
Rotating Disk ◽  
Deposition Process ◽  
Video Camera ◽  
Rossby Number ◽  
High Speed Video Camera ◽  
Water Drops ◽  
The Impact

Experimental studies of a water drop impinging on a rotating disk using a high-speed video camera have been performed. The photos of the impact were analyzed in detail. Three kinds of the deposition patterns were observed with the variation in Rossby number. It is found that Rossby number plays an important role in the deposition process of the drop impacting on the rotating disk, leading to some new stages not observed for drop impact on a stationary plate.

scholarly journals RESOURCE-SAVING TECHNOLOGIES FOR DEVELOPMENT OF MINERAL DEPOSITS

2021 ◽  
Vol 13 (3) ◽  
pp. 406-415
Author(s):  
Jaroslaw RYBAK ◽  
◽  
Marat KHAIRUTDINOV ◽  
Yulia TYULYAEVA ◽  
Cheynesh KONGAR-SYURYUN ◽  
...  
Keyword(s):  
High Speed ◽  
Negative Impact ◽  
Experimental Studies ◽  
Economic Feasibility ◽  
Historical Background ◽  
Mineral Deposits ◽  
Design Stage ◽  
Production Cycle ◽  
Resource Saving ◽  
The Impact

The relevance of the work is caused by the need to survive the mining industry during the protracted post-reform crisis and to minimize its negative impact on the ecology of the region through the development of technogenic mineral resources. Purpose of work. Substantiation of the possibility of replacing the traditional components of the filling composite with own or attracted man-made wastes after their processing to a level that meets the conditions of environmental safety and economic feasibility. Research methods: systematization, analysis and generalization of theoretical and experimental research in this area, as well as patent data. Results. A generalization is made, the result of an analysis of the mechanism and rates of accumulation of waste from mining and processing of mineral raw materials is given, and a multifactorial mathematical model of degradation of environmental ecosystems as a result of the impact of waste is formulated. A historical background is given and an assessment of the development of mineral deposits with backfilling with hardening mixtures based on utilized man-made waste in a closed cycle is given. A promising method of activating the binding components of the hardening mixture is recommended, treatment in a high-speed mill - disintegrator. The results of experimental studies of the possibility of using metallurgical slags of the Chusovoy metallurgical plant as a binder and as an inert filler of ore dressing wastes of PJSC Uralkali are given. It is shown that if the content of unrecovered metals in industrial waste is more than the background level, they can be disposed of after the extraction of metals within the framework of a single technological cycle of waste-free production. It is concluded that when preparing a filling composite, it is possible to replace traditional commercial components with man-made waste from mining and processing and metallurgical industries after extracting useful components from them and neutralizing hazardous impurities. The prospect of the transition of mining production to an innovative principle of organization, which excludes the storage of waste, is noted, for which it is advisable to combine physical-technical and physical-chemical technologies at the design stage in the technological process of resource development. Conclusions. The involvement of man-made waste in a closed production cycle increases the environmental and economic efficiency of enterprises. Conversion of production to minimize waste volumes and their use in their own or in related production is an effective step towards sustainable development of the mining region.

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