scholarly journals Two-layered plates of hexagonal and cubic crystals

2020 ◽  
pp. 101-115
Author(s):  
Михаил Андреевич Волков ◽  
Александр Иванович Демин ◽  
Валентин Александрович Городцов ◽  
Дмитрий Сергеевич Лисовенко
Keyword(s):  
Numerical Analysis ◽  
Young’S Modulus ◽  
Layer Thickness ◽  
Young's Modulus ◽  
Great Influence ◽  
Layered Plate ◽  
Coordinate Systems ◽  
Layered Plates ◽  
Cubic Crystals ◽  
Layer Thickness Ratio

Рассмотрена задача продольного растяжения двухслойных пластин из гексагональных и кубических кристаллов при различной ориентации слоев. Получены аналитические зависимости модуля Юнга и коэффициентов Пуассона пластин от отношения толщин. Проведен численный анализ изменчивости эффективных характеристик пластин из всех возможных комбинаций гексагональных и кубических кристаллов. Установлено, что существенное нарушение правила смесей для эффективного модуля Юнга двухслойной пластины происходит, если один из двух слоев заполняет ауксетик. Эффективный модуль Юнга может превосходить модули Юнга кристаллов в обоих слоях близкой жесткости. Отношение модулей Юнга кристаллов в обоих слоях оказывает существенное влияние и на эффективный коэффициент Пуассона. The problem of longitudinal tesnsion of two-layered plate of hexagonal and cubic crystals with different orientations of crystallophysic coordinate systems is discussed. Analytical dependences of effective Young’s modulus and Poisson’s ratios on layer thickness ratio are obtained. Numerical analysis of plates from all possible combinations of hexagonal and cubic crystals is performed. It is established that significant deviation of effective Young’s modulus values from predictions by mixture rule takes place in the case when one of the layers is auxetic. Effective Young’s modulus can have greater value than values of Young’s modulus of crystals at both layers. The ratio of Young’s modulus of crystals has great influence on the value of effective Poisson’s ratio.

scholarly journals Evaluating Mechanical Properties of Thin Layers using Nanoindentation and Finite-Element Modeling: Implanted Metals and Deposited Layers

1996 ◽  
Vol 438 ◽  
Author(s):  
J. A. Knapp ◽  
D. M. Follstaedt ◽  
J. C. Barbour ◽  
S. M. Myers ◽  
J. W. Ager ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Layer Thickness ◽  
Young's Modulus ◽  
Thin Layers ◽  
Element Modeling ◽  
Surface Modified

AbstractWe present a methodology based on finite-element modeling of nanoindentation data to extract reliable and accurate mechanical properties from thin, hard films and surface-modified layers on softer substrates. The method deduces the yield stress, Young's modulus, and hardness from indentations as deep as 50% of the layer thickness.

The Estimation of the Mechanical Property of the Porous Material by Numerical Analysis

2015 ◽  
Vol 656-657 ◽  
pp. 14-17
Author(s):  
Takeshi Gonda ◽  
Shigeru Ohtsuka ◽  
Masaki Yakabe ◽  
Yasutaka Hayamizu
Keyword(s):  
Mechanical Property ◽  
Numerical Analysis ◽  
Porous Materials ◽  
Young’S Modulus ◽  
Pore Diameter ◽  
Young's Modulus ◽  
Analysis Software ◽  
Metal Sample ◽  
Sintered Metal ◽  
Porosity Changes

Porous materials, such as filters made of sintered metals, lagging materials, and fireproof materials, are utilized in various fields. The porosity changes the characteristics of the materials. For example, with heat-insulating foam, the higher the porosity, the greater is the insulation factor. However, increased porosity leads to a decline in mechanical properties. Thus, when using porous materials, analyzing the mechanical strength is necessary. We modeled a porous structure of sintered metal sample and estimated the Young's modulus using the numerical analysis software “ADVENTURE” and compared the estimated value with the experimental value. Also, we modeled the effect of porosity and pore diameter on the mechanical property of the material. From the results, the Young's modulus decreases with increases in porosity and pore diameter, as expected.

Dynamic Responses of Plates With Viscoelastic Free Layer Damping Treatment

1996 ◽  
Vol 118 (3) ◽  
pp. 362-367 ◽  
Author(s):  
Sung Yi ◽  
M. Fouad Ahmad ◽  
H. H. Hilton
Keyword(s):  
Young’S Modulus ◽  
Layer Thickness ◽  
Young's Modulus ◽  
Dynamic Responses ◽  
Viscoelastic Damping ◽  
Free Layer ◽  
Modulus Ratio ◽  
Transient Responses ◽  
Damping Materials

Dynamic transient responses of plates with viscoelastic free damping layers are studied in order to evaluate free layer damping treatment performances. The effects of forcing frequencies and temperatures on free-layer viscoelastic damping treatment of plates are investigated analytically. Young’s modulus ratio of structures to viscoelastic damping materials and the damping layer thickness effects on the damping ability are also explored.

Influence of specimen configuration on the measurement of the off-axis Young’s modulus of wood by vibration tests

Holzforschung ◽  
2012 ◽  
Vol 66 (4) ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Numerical Analysis ◽  
Young’S Modulus ◽  
Test Data ◽  
Young's Modulus ◽  
Flexural Vibration ◽  
Solid Wood ◽  
Vibration Tests

Abstract To determine the Young’s modulus of solid wood, longitudinal and flexural vibration methods are very effective because the Young’s modulus can be measured non-destructively. When the specimen has an off-axis angle, however, the specimen configuration has an influence on the measurement of Young’s modulus. Therefore, it is important to reveal the influence of specimen configuration on the measurement of off-axis Young’s modulus. In this research, the off-axis Young’s modulus of wood was obtained by conducting longitudinal and flexural vibration tests using specimens with various widths and performing a subsequent numerical analysis on the test data. The off-axis Young’s modulus was dependent on specimen configuration when the off-axis angle ranged from approximately 5° to 15° because the bending and torsional deformations in the longitudinal and flexural vibration tests, respectively, were significant in this range.

scholarly journals The Extreme Values of Young’s Modulus and the Negative Poisson’s Ratios of Rhombic Crystals

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 863
Author(s):  
Valentin A. Gorodtsov ◽  
Dmitry S. Lisovenko
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Extreme Values ◽  
Young's Modulus ◽  
Sufficient Conditions ◽  
Poisson's Ratio ◽  
Cubic Crystals ◽  
Special Cases ◽  
Function Of Two Variables ◽  
Necessary And Sufficient

The extreme values of Young’s modulus for rhombic (orthorhombic) crystals using the necessary and sufficient conditions for the extremum of the function of two variables are analyzed herein. Seven stationary expressions of Young’s modulus are obtained. For three stationary values of Young’s modulus, simple analytical dependences included in the sufficient conditions for the extremum of the function of two variables are revealed. The numerical values of the stationary and extreme values of Young’s modulus for all rhombic crystals with experimental data on elastic constants from the well-known Landolt-Börnstein reference book are calculated. For three stationary values of Young’s modulus of rhombic crystals, a classification scheme based on two dimensionless parameters is presented. Rhombic crystals ((CH3)3NCH2COO·(CH)2(COOH)2, I, SC(NH2)2, (CH3)3NCH2COO·H3BO3, Cu-14 wt%Al, 3.0wt%Ni, NH4B5O8·4H2O, NH4HC2O4·1/2H2O, C6N2O3H6 and CaSO4) having a large difference between maximum and minimum Young’s modulus values were revealed. The highest Young’s modulus among the rhombic crystals was found to be 478 GPa for a BeAl2O4 crystal. More rigid materials were revealed among tetragonal (PdPb2; maximum Young’s modulus, 684 GPa), hexagonal (graphite; maximum Young’s modulus, 1020 GPa) and cubic (diamond; maximum Young’s modulus, 1207 GPa) crystals. The analytical stationary values of Young’s modulus for tetragonal, hexagonal and cubic crystals are presented as special cases of stationary values for rhombic crystals. It was found that rhombic, tetragonal and cubic crystals that have large differences between their maximum and minimum values of Young’s modulus often have negative minimum values of Poisson’s ratio (auxetics). We use the abbreviated term auxetics instead of partial auxetics, since only the latter were found. No similar relationship between a negative Poisson’s ratio and a large difference between the maximum and minimum values of Young’s modulus was found for hexagonal crystals.

scholarly journals Characterizing the Frequency Response of Compliant Materials by Laser Döppler Vibrometry Coupled Acoustic Excitation

Vibration ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 64-74
Author(s):  
Arlindo Ricarte ◽  
José Meireles ◽  
Octávio Inácio
Keyword(s):  
Numerical Analysis ◽  
Frequency Response ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Dynamic Mechanical Properties ◽  
Laser Doppler ◽  
Acoustic Excitation ◽  
Laser Doppler Vibrometry ◽  
Dynamic Young’S Modulus ◽  
Dynamic Young's Modulus

Low-stiffness or compliant materials are inherently difficult to characterize in terms of dynamic mechanical properties. Their free-vibration behavior is not frequently analyzed, given that performing classic vibration testing in these type of materials may imply the tampering of the results by external sources, either by changes in the geometry of the sample, by gravity-induced buckling, or the instrumentation itself (e.g., the mass of accelerometers). This study proposes an approach to determine the frequency response of these types of materials, using a noncontact methodology based on acoustic excitation and displacement measurement by Laser Döppler Vibrometry. The detailed method may be optimized by changing the sample design into a half-cane configuration to increase sample stiffness. This approach significantly increases the sample eigenmodes, facilitating their excitation by the acoustic pressure source. Numerical analysis using the values of the dynamic Young’s modulus from the experimental approaches validates the overall procedure. It is shown that the combination of numerical analysis and the proposed experimental method is a possible route for the determination of the dynamic Young’s modulus of these types of materials by inverse engineering.

Optimization of fused deposition modeling process parameters using the Taguchi method to improve the tensile properties of 3D-printed polyether ether ketone

2021 ◽  
pp. 146442072110175
Author(s):  
Timoumi Mohamed ◽  
Najoua Barhoumi ◽  
Khalid Lamnawar ◽  
Abderrahim Maazouz ◽  
Amna Znaidi
Keyword(s):  
Tensile Properties ◽  
Young’S Modulus ◽  
Layer Thickness ◽  
Process Parameters ◽  
Fused Deposition Modeling ◽  
Young's Modulus ◽  
Fused Deposition ◽  
Polyether Ether Ketone ◽  
Deposition Modeling ◽  
Ether Ketone

The interesting mechanical properties of polyether ether ketone give the material a place among the foremost competitors when it comes to replacing metal. Fused deposition modeling has been recognized as an alternative method to process polyether ether ketone parts. In this study, the effect of different process parameters such as nozzle, bed, and radiant temperatures as well as printing speed and layer thickness on the tensile properties of three-dimensional printed polyether ether ketone was investigated. The optimization of the tensile properties of PEEK were studied by performing a reduced number of experiments, using the experimental design method based on the Taguchi approach which limits the number of experiments to 8 instead of 32. Results showed that a decent Young’s modulus was found by setting the nozzle temperature, print speed, and bed temperatures to their high levels and by setting the layer thickness and radiant temperature to their low level. Using these parameters, a Young’s modulus of 3.5 GPa was obtained, which represents 87.5% of the value indicated in the technical sheet. With these settings, we also found a tensile strength of 45.5 MPa, which corresponds to 46.4% of the value given by the studied polyether ether ketone material. A scanning electron microscopic investigation of the porosity and interlayer adhesion, confirmed that a higher bed temperature also tended to promote adhesion between layers.

Dynamic Responses of Plates With Viscoelastic Damping Treatment

1993 ◽  
Author(s):  
Sung Yi ◽  
M. Fouad Ahmad ◽  
Harry H. Hilton
Keyword(s):  
Young’S Modulus ◽  
Layer Thickness ◽  
Young's Modulus ◽  
Dynamic Responses ◽  
Viscoelastic Damping ◽  
Free Layer ◽  
Modulus Ratio ◽  
Transient Responses ◽  
Damping Materials

Abstract Dynamic transient responses of plates with free damping layers are studied in order to evaluate free layer damping treatment performances. The effects of forcing frequencies and temperatures on free-layer viscoelastic damping treatment of plates are investigated analytically. Young’s modulus ratio of structures to viscoelastic damping materials and the damping layer thickness effects on the damping ability are also explored.

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