scholarly journals Elastic Properties of Statistically Equivalent Materials With Varying Individual Grain Orientations

1995 ◽  
Vol 25 (1) ◽  
pp. 17-24 ◽  
Author(s):  
H. Kiewel ◽  
H. J. Bunge ◽  
L. Fritsche
Keyword(s):  
Elastic Properties ◽  
Displacement Field ◽  
Elastic Moduli ◽  
Local Deformation ◽  
Deformation Field ◽  
Copper Metal ◽  
Bcc Lattice ◽  
Real Material ◽  
Different Types ◽  
Grain Orientations

The elastic properties of copper metal with different individual grain orientations exhibiting the same texture are determined. We simulate the real material by two different types of clusters. The first one consists of 365 cubic grains, the second cluster is an arrangement of 181 Wigner-Seitz cells of a body centred cubic (bcc)-lattice. For each type of cluster we let the local grain orientations vary. The displacement field inside these aggregates as a result of a homogeneous deformation acting on the surface of the clusters is calculated. Although the resulting local deformation field for different individual grain orientations varies strongly, the macroscopic elastic moduli are in the frame of this simulation identical for any cluster of the same type, as it has to be for statistically equivalent materials.

scholarly journals Polystyrene-Based Nanocomposites with Different Fillers: Fabrication and Mechanical Properties

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2457
Author(s):  
Olga A. Moskalyuk ◽  
Andrey V. Belashov ◽  
Yaroslav M. Beltukov ◽  
Elena M. Ivan’kova ◽  
Elena N. Popova ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Elastic Moduli ◽  
Spherical Particles ◽  
Linear Elastic ◽  
Rigid Particles ◽  
Different Types ◽  
Non Linear ◽  
Multi Walled Carbon Nanotubes ◽  
Carbon Fillers ◽  
Walled Carbon Nanotubes

The paper presents a comprehensive analysis of the elastic properties of polystyrene-based nanocomposites filled with different types of inclusions: small spherical particles (SiO2 and Al2O3), alumosilicates (montmorillonite, halloysite natural tubules and mica), and carbon nanofillers (carbon black and multi-walled carbon nanotubes). Block samples of composites with different filler concentrations were fabricated by melt technology, and their linear and non-linear elastic properties were studied. The introduction of more rigid particles led to a more profound increase in the elastic modulus of a composite, with the highest rise of about 80% obtained with carbon fillers. Non-linear elastic moduli of composites were shown to be more sensitive to addition of filler particles to the polymer matrix than linear ones. A non-linearity modulus βs comprising the combination of linear and non-linear elastic moduli of a material demonstrated considerable changes correlating with those of the Young’s modulus. The changes in non-linear elasticity of fabricated composites were compared with parameters of bulk non-linear strain waves propagating in them. Variations of wave velocity and decay decrement correlated with the observed enhancement of materials’ non-linearity.

scholarly journals Numerical estimation of interface roughness effect on upscaled elastic properties of layered media

2020 ◽  
pp. 225-240
Author(s):  
Т.С. Хачкова ◽  
В.В. Лисица ◽  
Д.Р. Колюхин ◽  
Г.В. Решетова
Keyword(s):  
Elastic Properties ◽  
Numerical Algorithm ◽  
Elastic Moduli ◽  
Numerical Study ◽  
Layered Media ◽  
Interface Roughness ◽  
Numerical Estimation ◽  
Roughness Effect ◽  
Equivalent Models ◽  
Different Types

Представлено численное исследование влияния шероховатости границ раздела в слоистой среде на эффективные упругие свойства тонкослоистой среды. Предложен алгоритм построения статистически эквивалентных моделей слоистых сред двух различных типов. Первый тип включает в себя модели с постоянными упругими параметрами, но с шероховатой границей раздела. Второй тип состоит из моделей с плоскими границами раздела, но с параметрами, задаваемыми случайными величинами. При этом распределение упругих параметров в моделях второго типа (средние значения и ковариационная матрица) однозначно определяется шероховатостью границ раздела (длина корреляции и стандартное отклонение) в моделях первого типа. We discuss a numerical study of the interface roughness effect on elastic moduli of an upscaled model of layered media. We propose a numerical algorithm to construct statistically equivalent models of two different types. The first type includes the models with constant elastic moduli but with rough interfaces. The second type consists of models with flat interfaces but with stochastic elastic moduli. It is shown that the distribution of the elastic moduli for the models of the second type is uniquely determined by the interface roughness in the models of the first type.

scholarly journals Sensitivity of Ultrasonic Coda Wave Interferometry to Material Damage—Observations from a Virtual Concrete Lab

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4033
Author(s):  
Claudia Finger ◽  
Leslie Saydak ◽  
Giao Vu ◽  
Jithender J. Timothy ◽  
Günther Meschke ◽  
...  
Keyword(s):  
Elastic Moduli ◽  
Concrete Specimen ◽  
Coda Wave ◽  
Velocity Change ◽  
Damage Scenarios ◽  
Different Types ◽  
Source Signal ◽  
The Impact ◽  
Structural Scale ◽  
Coda Wave Interferometry

Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion of the ultrasonic wavefield, the coda, is sensitive to small changes in the elastic moduli of the material. Coda Wave Interferometry (CWI) correlates these small changes in the coda with the wavefield recorded in intact, or unperturbed, concrete specimen to reveal the amount of velocity change that occurred. CWI has the potential to detect localized damages and global velocity reductions alike. In this study, the sensitivity of CWI to different types of concrete mesostructures and their damage levels is investigated numerically. Realistic numerical concrete models of concrete specimen are generated, and damage evolution is simulated using the discrete element method. In the virtual concrete lab, the simulated ultrasonic wavefield is propagated from one transducer using a realistic source signal and recorded at a second transducer. Different damage scenarios reveal a different slope in the decorrelation of waveforms with the observed reduction in velocities in the material. Finally, the impact and possible generalizations of the findings are discussed, and recommendations are given for a potential application of CWI in concrete at structural scale.

scholarly journals A Methodology to Validate the InSAR Derived Displacement Field of the September 7th, 1999 Athens Earthquake Using Terrestrial Surveying. Improvement of the Assessed Deformation Field by Interferometric Stacking

Sensors ◽  
2008 ◽  
Vol 8 (7) ◽  
pp. 4119-4134 ◽  
Author(s):  
Ioannis Kotsis ◽  
Charalabos Kontoes ◽  
Dimitrios Paradissis ◽  
Spyros Karamitsos ◽  
Panagiotis Elias ◽  
...  
Keyword(s):  
Displacement Field ◽  
Deformation Field ◽  
Athens Earthquake

Measurement and Analysis of Triboelectric Surface Charge

2021 ◽  
Vol 30 (1/2) ◽  
pp. 7-11
Author(s):  
Jinhong PARK ◽  
Jinhyeok CHOI ◽  
Sang Hyeok PARK ◽  
Minbaek LEE
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Surface Properties ◽  
Elastic Moduli ◽  
Surface Charges ◽  
Contact Electrification ◽  
Measurement And Analysis ◽  
Different Types ◽  
Triboelectric Charging ◽  
Method Of Measurement

Contact electrification occurs when two isolated objects come into contact. Such a phenomenon led humans to first realization of the existence of electricity. Until now, the main causes of the triboelectric charging phenomenon have generally been thought to be the transfer of electrons, ions, and materials. This article, however, is limited to electron transfer on the surface, which is regarded as a general case not limited to specific situations. The contact between two objects occurs between the two surfaces; therefore, the surface properties of the material under examination are the most important properties in triboelectric charge transfer. The surface properties may include the types of materials in contact, their energy states, the roughnesses of their surfaces, and their elastic moduli. In this regard, we introduce here the current understanding of the energy band structures involved in the different types of materials, the method of measurement, an analysis of surface charges, and related applications.

Stochastic Properties of Anisotropic Materials

2001 ◽  
Author(s):  
Michael “Mick” Peterson ◽  
Miao Sun
Keyword(s):  
Elastic Properties ◽  
Anisotropic Materials ◽  
Optimal Recovery ◽  
Growth Patterns ◽  
Curvilinear Coordinates ◽  
Natural Material ◽  
Materials Properties ◽  
Damping Characteristics ◽  
Different Types ◽  
Stochastic Properties

Abstract Extensive research has been directed toward the development of methods for the optimal recovery of elastic properties from ultrasonic measurements. For a number of applications both the elastic and damping characteristics of the materials are required in design. The use of the optimal recovery does present challenges when applied to either man-made or natural anisotropic materials. In many cases manufacturing variability results in a need for a statistical description of the elastic and damping properties. In addition, errors in material lay-up or growth patterns may result in mis-orientation of the principle materials axes with respect to the geometrical axes. In this work, an examples is shown that demonstrates the recovery of the elastic properties of a natural material when stochastic properties are required. Statistical descriptions of the materials properties are obtained for wood of two different types of material. Results are shown assuming a nominally orthotropic orientation, although the existence of curvilinear coordinates is acknowledged.

Determination of DC06+ZE Sheet Crack Cause

2016 ◽  
Vol 368 ◽  
pp. 121-125
Author(s):  
Pavel Kejzlar ◽  
Tomáš Pilvousek ◽  
Michal Tregler
Keyword(s):  
Stress Concentration ◽  
Tensile Stress ◽  
Deep Drawing ◽  
Crack Formation ◽  
Local Stress ◽  
Local Deformation ◽  
Local Stress Concentration ◽  
Bcc Lattice ◽  
Hard Particles

The present work deals with determination of the cause of crack occurring in a part of car body manufactured from deep-drawing sheet. UHR-SEM, EDS, EBSD and measurement of microhardness were used for evaluation of the structure, local deformation and crack formation mechanism. A material analysis discovered foreign particles in the material. These particles were identified as MgAl2O4 with BCC lattice. The occurrence of these hard particles led to local stress concentration, decrease in mechanical strength and sheet breach due to tensile stress during deformation.

Elastic properties and phonon conductivities of Ti3Al(C0.5,N0.5)2 and Ti2Al(C0.5,N0.5) solid solutions

2008 ◽  
Vol 23 (6) ◽  
pp. 1517-1521 ◽  
Author(s):  
M. Radovic ◽  
A. Ganguly ◽  
M.W. Barsoum
Keyword(s):  
Elastic Properties ◽  
Solid Solutions ◽  
Room Temperature ◽  
Elastic Moduli ◽  
Unit Cell ◽  
Young’S Moduli ◽  
Temperature Shear ◽  
End Members ◽  
Cell Volumes ◽  
Thermal Conductivities

Herein we compare the lattice parameters, room temperature shear and Young’s moduli, and phonon thermal conductivities of Ti2AlC0.5N0.5 and Ti3Al(C0.5, N0.5)2 solid solutions with those of their end members, namely Ti2AlC, Ti2AlN, Ti3AlC2, and Ti4AlN2.9. In general, the replacement of C by N decreases the unit cell volumes and increases the elastic moduli and phonon thermal conductivities. The increase in the latter two properties, however, is sensitive to the concentrations of defects, most likely vacancies on one or more of the sublattices.

Dependence of the Elastic Properties of a Single-Walled Carbon Nanotube on its Chirality

2018 ◽  
Vol 284 ◽  
pp. 20-24
Author(s):  
E.S. Sergeeva
Keyword(s):  
Carbon Nanotube ◽  
Elastic Properties ◽  
Single Walled Carbon Nanotubes ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Extreme Loads ◽  
Structure Sensitive ◽  
Different Types ◽  
Walled Carbon Nanotubes ◽  
Elastic Characteristics

Currently, composite materials composed of a matrix and reinforcing components are widely used as a structural material for various engineering devices designed to operate under extreme loads of different types. By modifying a composite with structure-sensitive inclusions, such as a single-wall carbon nanotube, the mechanical properties, especially elastic characteristics, of the resulting material can be significantly improved. The results of investigation of a single-walled carbon nanotubes chirality influence on its elastic properties are presented. Various configurations of nanotubes, such as zigzag and armchair are considered. The dependences of the nanotube bulk modulus and shear modulus of its diameter are shown.

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