Advanced Manufacturing from Macro- to Nanoscale: Impact and Shock Loading

2018 ◽  
Vol 910 ◽  
pp. 58-63
Author(s):  
Athanasios G. Mamalis
Keyword(s):  
Biomedical Engineering ◽  
High Speed ◽  
Shock Loading ◽  
Industrial Applications ◽  
Plenary Lecture ◽  
Advanced Materials ◽  
Advanced Manufacturing ◽  
High Speed Impact ◽  
International Team ◽  
Over 40 Years

Trends and developments in advanced manufacturing from macro- to nanoscale, mainly associated with nanotechnology, precision/ultraprecision manufacturing and advanced materials under low/high speed impact and shock loading, with industrial applications to net-shape manufacturing, biomedical engineering, energy and transport, an outcome of the very extensive work over 40 years on these fields performed by the author and his research international team, are briefly outlined in the present Plenary Lecture of the 5th ESHP 2016 Symposium.

Advanced Manufacturing under Shock

2018 ◽  
Vol 915 ◽  
pp. 253-258
Author(s):  
Athanasios G. Mamalis
Keyword(s):  
Shock Loading ◽  
Industrial Research ◽  
Industrial Applications ◽  
Advanced Materials ◽  
Advanced Manufacturing ◽  
International Team ◽  
Recent Trends ◽  
Points Of View ◽  
Over 40 Years

Some recent trends and developments in advanced manufacturing of advanced materials from macro-to nanoscale subjected to shock loading, i.e. the up-to-date very important engineering area from industrial, research and academic points of view, with industrial applications to net-shape manufacturing, bioengineering, energy and safety, an outcome of the very extensive, over 40 years, work on this field performed by the author and his research international team, are briefly outlined.

Shock Loading of Advanced Materials from Macro-, Micro- to Nanoscale

2014 ◽  
Vol 792 ◽  
pp. 3-14
Author(s):  
Athanasios G. Mamalis
Keyword(s):  
Shock Loading ◽  
Scientific Research ◽  
Industrial Applications ◽  
Point Of View ◽  
Advanced Materials ◽  
Research Center ◽  
Advanced Manufacturing ◽  
Kurchatov Institute ◽  
Recent Trends ◽  
Russian Research

Some of the activities of the Project Center for Nanotechnology and Advanced Engineering (PC-NAE), a joint initiative of the Greek National Center for Scientific Research Demokritos and the Russian Research Center Kurchatov Institute, in advanced manufacturing engineering are briefly outlined, focusing onto some recent trends and developments in manufacturing from macro-, micro-, to nanoscale of advanced materials in the important engineering topics nowadays from industrial, research and academic point of view: nanotechnology/ultraprecision engineering and advanced materials under shock loading, with industrial applications to net-shape manufacturing, bioengineering, energy and transport.

Dynamics of Planar, Elastic, High-Speed Mechanisms Considering Three-Dimensional Offset Geometry: Analytical and Experimental Investigations

1983 ◽  
Vol 105 (3) ◽  
pp. 498-510 ◽  
Author(s):  
F. R. Stamps ◽  
C. Bagci
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Shock Loading ◽  
Dynamic Stress ◽  
Three Dimensional ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Planar Mechanisms ◽  
Elastic Systems ◽  
Stress Levels

Mechanisms in industrial applications in general operate as three-dimensional elastic systems, including planar mechanisms due to offsets between the planes of motion of links. This article investigates dynamic behaviors of planar mechanisms with offset geometry analytically and experimentally for dynamic stress and critical speed levels. Three-dimensional line element with irregular freedoms is used and generalized digital computer programs are prepared to perform kineto-elasto-static, dynamic stress, frequency, and critical speed analyses of three-dimensional mechanisms including the planar mechanisms with three-dimensional offsets. An experimental planar four-bar mechanism was tested for critical speed and elastodynamic stress levels with three levels of offsets. It has been determined that a mechanism experiences integer divisions of the integrated average of the three-dimensional fundamental natural frequency, ωinavg, within a cycle of the mechanism as critical speeds as well as its multiples. Recommended operating speeds of a mechanism are those in between two integer divisions of ωinavg at lower levels. Elastodynamic stress levels at these recommended speed levels are predicted analytically by kineto-elasto-static analysis and very conservatively even in the shock loading zones of the mechanism. The validity of the highly economical CGKES (Critical Geometry Kineto-Elasto-Statics) method for mechanisms having three-dimensional geometry is also verified by the experimental results.

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.

Processing of Advanced Materials Using Conventional and Shock Techniques

2007 ◽  
Vol 566 ◽  
pp. 141-148
Author(s):  
A.G. Mamalis
Keyword(s):  
Solar Energy ◽  
Nanostructured Materials ◽  
Biomedical Engineering ◽  
Manufacturing Technology ◽  
Point Of View ◽  
Advanced Materials ◽  
Advanced Manufacturing ◽  
Materials Synthesis ◽  
Energy Devices ◽  
Recent Trends

Some of the activities of the Laboratory of Manufacturing Technology of the NTUA in manufacturing engineering are reported, focusing onto some recent trends and developments in advanced manufacturing of advanced materials, in the important engineering topics nowadays from industrial, research and academic point of view: nanotechnology/nanostructured materials, synthesis and net-shape fabrication of superconductors, biomedical engineering and solar energy devices.

scholarly journals Determining the Velocity of Hypersonic Compact Elements in Ground Testing Plants

2019 ◽  
pp. 65-72
Author(s):  
S.I. Gerasimov ◽  
I.A. Odzeriho ◽  
R.V. Gerasimova ◽  
B.A. Yanenko
Keyword(s):  
Shock Wave ◽  
High Speed ◽  
Shock Loading ◽  
Experimental Testing ◽  
Complex Structures ◽  
Ground Testing ◽  
High Speed Impact ◽  
Condensed Explosives ◽  
Hypersonic Speeds ◽  
The Impact

Protection of spacecraft from high-speed impact when encountering meteorite particles and man-made debris is currently a pressing issue. This article presents methods for determining the reaction of complex structures to the impact of particles with cosmic velocities. To determine the anti-meteorite resistance of materials and structures and to study the reaction of materials under high-intensity shock loading, schemes are developed for the production and registration of high-speed metal compact elements moving at hypersonic speeds using cumulative explosive throwing devices based on high-power condensed explosives. The use of the ‘hemisphere-cylinder’ shaped lining made it possible to test a shaped charge, consistently forming a steel compact element with a velocity of 6 km/s. The paper presents the results of numerical calculations and experimental testing of such a booster. Using this device, a method for determining the speed of the hypersonic striker pin is developed based on visualization of the head shock wave at the entrance of the striker into water.

Chitosan in Biomedical Engineering: A Critical Review

2019 ◽  
Vol 14 (2) ◽  
pp. 93-116 ◽  
Author(s):  
Shabnam Mohebbi ◽  
Mojtaba Nasiri Nezhad ◽  
Payam Zarrintaj ◽  
Seyed Hassan Jafari ◽  
Saman Seyed Gholizadeh ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Biomedical Engineering ◽  
Biological Properties ◽  
Advanced Materials ◽  
Comprehensive Overview ◽  
Chemical Structures ◽  
Bio Imaging ◽  
Significant Attention ◽  
Unique Chemical

Biomedical engineering seeks to enhance the quality of life by developing advanced materials and technologies. Chitosan-based biomaterials have attracted significant attention because of having unique chemical structures with desired biocompatibility and biodegradability, which play different roles in membranes, sponges and scaffolds, along with promising biological properties such as biocompatibility, biodegradability and non-toxicity. Therefore, chitosan derivatives have been widely used in a vast variety of uses, chiefly pharmaceuticals and biomedical engineering. It is attempted here to draw a comprehensive overview of chitosan emerging applications in medicine, tissue engineering, drug delivery, gene therapy, cancer therapy, ophthalmology, dentistry, bio-imaging, bio-sensing and diagnosis. The use of Stem Cells (SCs) has given an interesting feature to the use of chitosan so that regenerative medicine and therapeutic methods have benefited from chitosan-based platforms. Plenty of the most recent discussions with stimulating ideas in this field are covered that could hopefully serve as hints for more developed works in biomedical engineering.

scholarly journals Fingerprinting shock-induced deformations via diffraction

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Avanish Mishra ◽  
Cody Kunka ◽  
Marco J. Echeverria ◽  
Rémi Dingreville ◽  
Avinash M. Dongare
Keyword(s):  
High Speed ◽  
Shock Loading ◽  
Dislocation Slip ◽  
Line Profiles ◽  
X Ray Diffraction ◽  
Final State ◽  
X Ray ◽  
Shock Testing ◽  
Local Pressures ◽  
Deformation Modes

AbstractDuring the various stages of shock loading, many transient modes of deformation can activate and deactivate to affect the final state of a material. In order to fundamentally understand and optimize a shock response, researchers seek the ability to probe these modes in real-time and measure the microstructural evolutions with nanoscale resolution. Neither post-mortem analysis on recovered samples nor continuum-based methods during shock testing meet both requirements. High-speed diffraction offers a solution, but the interpretation of diffractograms suffers numerous debates and uncertainties. By atomistically simulating the shock, X-ray diffraction, and electron diffraction of three representative BCC and FCC metallic systems, we systematically isolated the characteristic fingerprints of salient deformation modes, such as dislocation slip (stacking faults), deformation twinning, and phase transformation as observed in experimental diffractograms. This study demonstrates how to use simulated diffractograms to connect the contributions from concurrent deformation modes to the evolutions of both 1D line profiles and 2D patterns for diffractograms from single crystals. Harnessing these fingerprints alongside information on local pressures and plasticity contributions facilitate the interpretation of shock experiments with cutting-edge resolution in both space and time.

scholarly journals Energy Absorption Characteristics of PVC Coarse Aggregate Concrete under Impact Load

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Shi Hu ◽  
Huaming Tang ◽  
Shenyao Han
Keyword(s):  
Compressive Strength ◽  
Energy Absorption ◽  
High Speed ◽  
Coarse Aggregate ◽  
Specific Energy Absorption ◽  
Low Speed ◽  
High Speed Impact ◽  
Aggregate Content ◽  
Dynamic Compressive Strength ◽  
Absorption Characteristics

AbstractIn this paper, polyvinyl chloride (PVC) coarse aggregate with different mixing contents is used to solve the problems of plastic pollution, low energy absorption capacity and poor damage integrity, which provides an important reference for PVC plastic concrete used in the initial support structures of highway tunnels and coal mine roadway. At the same time, the energy absorption characteristics and their relationship under different impact loads are studied, which provides an important reference for predicting the energy absorption characteristics of concrete under other PVC aggregate content or higher impact speed. This study replaced natural coarse aggregate in concrete with different contents and equal volume of well-graded flaky PVC particles obtained by crushing PVC soft board. Also, slump, compression, and splitting strength tests, a free falling low-speed impact test of steel balls and a high-speed impact compression test of split Hopkinson pressure bar (SHPB) were carried out. Results demonstrate that the static and dynamic compressive strength decreases substantially, and the elastic modulus and slump decrease slowly with the increase of the mixing amount of PVC aggregate (0–30%). However, the energy absorption rate under low-speed impact and the specific energy absorption per MPa under high-speed impact increase obviously, indicating that the energy absorption capacity is significantly enhanced. Regardless of the mixing amount of PVC aggregate, greater strain rate can significantly enhance the dynamic compressive strength and the specific energy absorption per MPa. After the uniaxial compression test or the SHPB impact test, the relative integrity of the specimen is positively correlated with the mixing amount of PVC aggregate. In addition, the specimens are seriously damaged with the increase of the impact strain rate. When the PVC aggregate content is 20%, the compressive strength and splitting strength of concrete are 33.8 MPa and 3.26 MPa, respectively, the slump is 165 mm, the energy absorption rate under low-speed impact is 89.5%, the dynamic compressive strength under 0.65 Mpa impact air pressure is 58.77 mpa, and the specific energy absorption value per MPa is 13.33, which meets the requirements of shotcrete used in tunnel, roadway support and other impact loads. There is a linear relationship between the energy absorption characteristics under low-speed impact and high-speed impact. The greater the impact pressure, the larger the slope of the fitting straight line. The slope and intercept of the fitting line also show a good linear relationship with the increase of impact pressure. The conclusions can be used to predict the energy absorption characteristics under different PVC aggregate content or higher-speed impact pressure, which can provide important reference for safer, more economical, and environmental protection engineering structure design.

Investigation on the mechanical properties of press-hardened boron steel sheets using the conductive heating technique

2020 ◽  
Vol 234 (8) ◽  
pp. 1084-1098
Author(s):  
O Kocar ◽  
H Livatyalı
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Boron Steel ◽  
Fast Heating ◽  
Heating Method ◽  
Conductive Heating ◽  
Press Hardening ◽  
High Speed Impact ◽  
Significant Difference ◽  
Structural Parts

An aluminized 22MnB5 (Boron) steel sheet, used for structural parts in the automotive industry, was subjected to press-hardening followed by austenitizing, both in a conventional furnace and via the conductive (electric resistance) heating method, an innovative technique based on the Joule’s principle for fast heating of the sheet metal. Conductive heating presents a number of advantages over the in-furnace heating method. These include a more efficient use of energy, as well as the requirement of less time and space for heating, thus lowering costs. After press-hardening was performed using both methods, the microstructural and mechanical characterizations of both specimens were examined for optical microscopy, hardness, tensile strength, and high-speed impact tests. The results showed that the press-hardening process transformed the ferritic–pearlitic microstructure in the as-received state into martensite after die quenching and caused a substantial increase in hardness and strength at the expense of ductility and impact toughness. On the other hand, no significant difference was observed in either the microstructure or mechanical properties with respect to the heating method used. The results obtained in the present investigation concur with the findings of current literature.

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