scholarly journals Optimisation of parameters for the production of perforated armour panels made of nanobainitic steel using dynamic hardness measurement methodology

2020 ◽  
Vol 71 (4) ◽  
pp. 12-18
Keyword(s):  
Dynamic Properties ◽  
Hardness Measurement ◽  
Measurement Methods ◽  
Dynamic Indentation ◽  
Dynamic Hardness ◽  
Bainitic Steels ◽  
Indentation Tests ◽  
Measurement Methodology ◽  
Dynamic Wear ◽  
Firing Tests

The study is a continuation of the development of material characteristics in order to expand the range of products for the production of which nanostructured bainitic steels can be used. The tests included measurement of dynamic properties important in the material qualification process for firing tests and for other applications requiring dynamic wear resistance. The novelty of the implemented development of the innovative grade of nanostructured steel and the technology of manufacturing products – including armour systems containing perforated panels made of this grade of steel, consisted in developing the basics of dynamic hardness measurement methods and dynamic indentation tests using a Gleeble simulator.

Dynamic Compressive Properties of the Mandibular Condylar Cartilage

2006 ◽  
Vol 85 (6) ◽  
pp. 571-575 ◽  
Author(s):  
E. Tanaka ◽  
E. Yamano ◽  
D.A. Dalla-Bona ◽  
M. Watanabe ◽  
T. Inubushi ◽  
...  
Keyword(s):  
Regional Difference ◽  
Dynamic Properties ◽  
Articular Surface ◽  
Loading Frequency ◽  
Condylar Cartilage ◽  
Dynamic Indentation ◽  
Mandibular Condylar Cartilage ◽  
Storage And Loss Moduli ◽  
Wide Range ◽  
Indentation Tests

The mandibular condylar cartilage plays an important role as a stress absorber during function. However, relatively little information is available on its dynamic properties under compression. We hypothesized that these properties are region-specific and depend on loading frequency. To characterize the viscoelastic properties of the condylar cartilage, we performed dynamic indentation tests over a wide range of loading frequencies. Ten porcine mandibular condyles were used; the articular surface was divided into 4 regions, anteromedial, anterolateral, posteromedial, and posterolateral. The dynamic complex, storage, and loss moduli increased with frequency, and these values were the highest in the anteromedial region. Loss tangent decreased with frequency from 0.68 to 0.17, but a regional difference was not found. The present results suggest that the dynamic compressive modulus is region-specific and is dependent on the loading frequency, which might have important implications for the transmission of load in the temporomandibular joint.

Automation of selected brazes' dynamic properties in high-temperatures' measurement process

2013 ◽  
Vol 18 (2-3) ◽  
pp. 33-41
Author(s):  
Dominik Sankowski ◽  
Marcin Bakala ◽  
Rafał Wojciechowski
Keyword(s):  
Surface Tension ◽  
High Temperatures ◽  
Dynamic Properties ◽  
Automatic Measurement ◽  
Measurement Methodology ◽  
Joining Process ◽  
Wetting Force ◽  
Research Grant

Abstract The good quality of several manufactured components frequently depends on solidliquid interactions existing during processing. Nowadays, the research in material engineering focuses also on modern, automatic measurement methods of joining process properties, i.a. wetting force and surface tension, which allows for quantitative determination of above mentioned parameters. In the paper, the brazes’ dynamic properties in high-temperatures’ measurement methodology and the stand for automatic determination of braze’s properties, constructed and implmented within the research grant nr KBN N N519 441 839 - An integrated platform for automatic measurement of wettability and surface tension of solders at high temperatures, are widely described

Nanoindentation Hardness of Compositionally Modulated Ti/TiN Multilayered Films

1997 ◽  
Vol 505 ◽  
Author(s):  
Eiji Kusano ◽  
Masaru Kitagawa ◽  
Hidehito Nanto ◽  
Akira Kinbara
Keyword(s):  
Flow Rate ◽  
Hardness Measurement ◽  
Film Deposition ◽  
Multilayered Films ◽  
Dynamic Hardness ◽  
Modulation Period ◽  
Compositional Modulation ◽  
Film Hardness ◽  
Control Pattern ◽  
Flow Rate Control

ABSTRACTA detailed study of microhardness of multilayered films has been strongly needed to reveal effects of film layer structures and deposition conditions on the film hardness. A nanoindentation method is a useful method to investigate mechanical properties of thin films prepared on substrate materials. In this respect we have deposited a several types of Ti/TiN multilayered films and estimated their hardness by a nanoindentation method. The desired compositional modulation was obtained by changing the flow rate of N2gas periodically using a computer system. The modulation period has been varied from 10 to 40nm by changing a flow rate control pattern. The total thickness of the film was about 500nm including the underlayer of the TiO2(50nm)/Ti(50nm) multilayer for all samples with different modulation period. Substrates used in the experiment were borosilicate glass and not heated during film deposition. The compositional distribution toward to the film depth orientation was estimated by Auger electron spectroscopy. The dynamic hardness of the films has been estimated by a nanoindenter as a function of the modulation period. It was found that there existed an optimum modulation period of 20nm to enhance the film hardness by multilayer structure.. The maximum value of microhardness obtained for the optimum modulation period was 29GPa, which was much larger than that of the monolithic TiN coating of 15GPa. The hardness measurement results show that the behavior for dynamic hardness was different from that for plastic deformation hardness obtained.

Study of the dynamic hardness of structural metal materials

2020 ◽  
Vol 86 (1) ◽  
pp. 57-61
Author(s):  
Aleksandr V. Ilinskiy ◽  
Alexey V. Fedorov ◽  
Ksenia A. Stepanova ◽  
Igor U. Kinzhagulov ◽  
Igor O. Krasnov
Keyword(s):  
Comparative Analysis ◽  
Standard Deviation ◽  
Energy Approach ◽  
Metallic Materials ◽  
Sample Standard Deviation ◽  
Dynamic Indentation ◽  
Dynamic Hardness ◽  
Structural Metal ◽  
Metal Materials ◽  
Hardness Values

The mechanical properties of structural metallic materials are the most important indicators of their quality. Different methods (i.e., the methods of Shore, Brinell, Rockwell, Leeb, Vickers, method of instrumental indentation, and others) are currently used for determination of the hardness — one of the most important mechanical characteristics of structural metal materials. Among them is the method of dynamic indentation first developed at the Institute of Applied Physics of the National Academy of Sciences of Belarus. With the goal of further developing of the method of dynamic indentation, we propose the procedures aimed at increasing the accuracy of assessing the hardness of structural metallic materials: parameters of the contact interaction of the indenter with the sample material (Brinell hardness values) were measured using a dynamic indentation (DI) device; the values of surface and volumetric dynamic hardness were calculated taking into account the characteristics obtained using a DI device; a comparative analysis of hardness estimates obtained by different approaches was carried out. As a result of the comparative analysis of the methods, as well as their experimental testing, it was shown that an increase in the accuracy of hardness assessment can be achieved by using the «energy» approach based on assessing the ratio of the total work to the volume of the recovered indentation upon dynamic indentation of structural metal materials. The use of the «energy» approach provided obtaining the sample standard deviation of the volumetric dynamic hardness values, which, in turn, was significantly lower than the sample standard deviation of the surface dynamic hardness values and data of the dynamic indentation device, which directly affects an increase in the accuracy of hardness estimation during dynamic indentation of structural metal materials. Proceeding from the «energy» approach, a new algorithm for processing the initial signal is proposed when the dynamic hardness is determined using a dynamic indentation device.

Effect of Strain Rate on the Dynamic Hardness in Metals

2007 ◽  
Vol 129 (4) ◽  
pp. 505-512 ◽  
Author(s):  
Amin H. Almasri ◽  
George Z. Voyiadjis
Keyword(s):  
Strain Rate ◽  
Experimental Results ◽  
Strain Rates ◽  
Rate Dependency ◽  
Dynamic Hardness ◽  
Loading Rates ◽  
Hardening Law ◽  
Dislocation Densities ◽  
Indentation Tests ◽  
Good Agreement

Traditionally, the hardness of materials is determined from indentation tests at low loading rates (static). However, considerably less work has been conducted in studying the dynamic hardness of materials using relatively high loading rates. In the present work, two models are used to predict strain rate dependency in hardness. The first model is a power law expression that is based on the dependence of the yield stress on the strain rate. This model is relatively simple in implementation, and it is quite easy to determine its parameters from simple uniaxial experiments. The second model is a micromechanical based model using Taylor’s hardening law. It utilizes the behavior of dislocation densities at high strain rates in metals in order to relate dynamic hardness to strain rates. The latter model also accounts for any changes in temperature that could exist. A finite element is also run and compared with the two models proposed in this work. Results from both models are compared with available experimental results for oxygen-free high-conductivity copper and 1018 cold rolled steel, and both models show reasonably good agreement with the experimental results.

scholarly journals Measurement problems of miniature electrical machines

2021 ◽  
Vol 1199 (1) ◽  
pp. 012095
Author(s):  
M Bodnicki
Keyword(s):  
Experimental Research ◽  
Dynamic Characteristics ◽  
Dynamic Properties ◽  
Dynamic Measurement ◽  
Measurement Methods ◽  
Electrical Machines ◽  
Time Constants ◽  
Static And Dynamic Characteristics ◽  
Original Measurement

Abstract The article presents the issue related to experimental research on the determination of static and dynamic properties of miniature electrical machines. The tested objects are, for example, micromotors with body diameters in the order of single millimetres, or linear drives with millimetre dimensions. The main measurement problems were presented and the specificity of these measurements was characterized. First of all, electromechanical time constants have small values due to small values of masses or mass moments of inertia. The force quantities (forces and torques) generated by such actuators also require the use of unconventional measuring transducers. The research may concern the identification of static and dynamic characteristics, but also methods of dynamic measurement of the quantities used in the control of such micromachines are presented. Practical examples of original measurement methods and systems are presented.

scholarly journals EVALUATION OF METALLIC MATERIALS PLASTICITY BY DYNAMIC INDENTATION METHOD

2017 ◽  
pp. 81-87 ◽  
Author(s):  
V. A. Rudnitsky ◽  
A. P. Kren ◽  
G. A. Lantsman
Keyword(s):  
Elastic Modulus ◽  
Metallic Materials ◽  
Dynamic Indentation ◽  
Indentation Method ◽  
Dynamic Hardness

The method of plasticity test of metallic materials realized by means of a dynamic dimpling of material by a spherical tip is offered. The measured value of plasticity is defined by a ratio of plastic and complete deformations in the formed indentation which considers influence of an elastic modulus of material. The dependence connecting plasticity and dynamic hardness of materials is received. Experiments on metals from 70 to 380 GPA having an elastic modulus and hardness up to 62 HRC are made.

scholarly journals Experimental study of the dynamic indentation damage in thermally shocked granite

2018 ◽  
Vol 51 (1) ◽  
pp. 10-26 ◽  
Author(s):  
Ahmad Mardoukhi ◽  
Mikko Hokka ◽  
Veli-Tapani Kuokkala
Keyword(s):  
Heat Shock ◽  
Split Hopkinson Pressure Bar ◽  
Numerical Models ◽  
Experimental Testing ◽  
Material Surface ◽  
Rock Surface ◽  
Dynamic Indentation ◽  
Rock Interaction ◽  
Indentation Tests ◽  
Heat Shocks

This paper presents an experimental procedure to study the effects of pre-existing cracks and damage on the rock behavior under dynamic indentation. To gain better understanding on the mechanism involved in percussive-rotary drilling procedure, a modified Split Hopkinson Pressure Bar device was used to carry out dynamic indentation tests, where rock drill buttons were impacted on rock samples with dimensions of 30 cm × 30 cm × 30 cm. Before the mechanical testing, the samples were thermally shocked using a plasma spray gun for periods of 3, 4, and 6 seconds. The plasma gun produces a powerful heat shocks on the rock sample, and even short exposures can change the surface structure of the samples and provide samples with different crack patterns and surface roughness for experimental testing. The effects of the heat shock damage on the dynamic indentation behavior of the rock were characterized with single- and triple-button indentation tests. The specific destruction work was used to characterize the effects of heat shocks on the material removal during dynamic indentation. The results show that the force-displacement response of the rock does not change much even if the rock surface is severely damaged by the heat shock, however, the destruction work decreases significantly. This means that the same loading removes more volume if the material surface is pre-damaged, and that the efficiency of the indentation process cannot be evaluated from the bit-rock interaction forces alone. The presented experimental framework can be a useful tool for the verification of numerical models where the rock microstructure and especially the microcracks are essential.

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