Using delaunay triangularization to characterize non-affine displacement fields during athermal, quasistatic deformation of amorphous solids

Soft Matter ◽  
2021 ◽  
Vol 17 (38) ◽  
pp. 8612-8623
Author(s):  
Weiwei Jin ◽  
Amit Datye ◽  
Udo D. Schwarz ◽  
Mark D. Shattuck ◽  
Corey S. O'Hern
Keyword(s):  
Displacement Field ◽  
Simple Shear ◽  
Strain Field ◽  
Local Strain ◽  
Amorphous Solid ◽  
Amorphous Solids ◽  
Displacement Fields

Representation of the local strain field using Delaunay triangularization and the associated quadrupolar, non-affine displacement field for an amorphous solid undergoing athermal, quasistatic simple shear.

scholarly journals Multiperiodic orbits from interacting soft spots in cyclically sheared amorphous solids

2021 ◽  
Vol 7 (33) ◽  
pp. eabg7685
Author(s):  
Nathan C. Keim ◽  
Joseph D. Paulsen
Keyword(s):  
Steady State ◽  
Simple Model ◽  
Amorphous Solid ◽  
Amorphous Solids ◽  
Driving Cycle ◽  
Displacement Fields ◽  
Closed Loops ◽  
Two Level Systems

When an amorphous solid is deformed cyclically, it may reach a steady state in which the paths of constituent particles trace out closed loops that repeat in each driving cycle. A remarkable variant has been noticed in simulations where the period of particle motions is a multiple of the period of driving, but the reasons for this behavior have remained unclear. Motivated by mesoscopic features of displacement fields in experiments on jammed solids, we propose and analyze a simple model of interacting soft spots—locations where particles rearrange under stress and that resemble two-level systems with hysteresis. We show that multiperiodic behavior can arise among just three or more soft spots that interact with each other, but in all cases it requires frustrated interactions, illuminating this otherwise elusive type of interaction. We suggest directions for seeking this signature of frustration in experiments and for achieving it in designed systems.

Strain analysis with nanometer resolution using a conventional transmission electron microsopy technique: electron diffraction contrast imaging revisited

1995 ◽  
Vol 53 ◽  
pp. 168-169
Author(s):  
Koenraad G F Janssens ◽  
Omer Van der Biest ◽  
Jan Vanhellemont ◽  
Herman E Maes ◽  
Robert Hull
Keyword(s):  
Electron Diffraction ◽  
Strain Field ◽  
Elastic Strain ◽  
Strain Analysis ◽  
Local Strain ◽  
Contrast Imaging ◽  
Strain Characterization ◽  
Physical Mechanisms ◽  
Diffraction Contrast ◽  
Transmission Electron

There is a growing need for elastic strain characterization techniques with submicrometer resolution in several engineering technologies. In advanced material science and engineering the quantitative knowledge of elastic strain, e.g. at small particles or fibers in reinforced composite materials, can lead to a better understanding of the underlying physical mechanisms and thus to an optimization of material production processes. In advanced semiconductor processing and technology, the current size of micro-electronic devices requires an increasing effort in the analysis and characterization of localized strain. More than 30 years have passed since electron diffraction contrast imaging (EDCI) was used for the first time to analyse the local strain field in and around small coherent precipitates1. In later stages the same technique was used to identify straight dislocations by simulating the EDCI contrast resulting from the strain field of a dislocation and comparing it with experimental observations. Since then the technique was developed further by a small number of researchers, most of whom programmed their own dedicated algorithms to solve the problem of EDCI image simulation for the particular problem they were studying at the time.

The Study in the Displacement Field near Crack of the Plexiglass by Frequency Domination Method of the White Speckle

2006 ◽  
Vol 306-308 ◽  
pp. 357-362 ◽  
Author(s):  
Xin Hua Ji ◽  
Fang Yu Xu ◽  
Jin Long Chen ◽  
Yu Wen Qin
Keyword(s):  
Light Source ◽  
Displacement Field ◽  
Vibration Isolation ◽  
Laser Speckle ◽  
Displacement Fields ◽  
Fracture Properties ◽  
Normal Environment

The fracture properties of Plexiglass bright the attentions of the researchers as it is the import material used in aero-planes industry The white speckle technique could obtain displacement fields nondestructively under the normal environment. Compare to the laser speckle method there are no interference light source and the vibration isolation needed. In the paper the principle of the technique is described and the displacement field near crack and SIF are measured. The results show that the technique is very suitable to the application in industry.

Development of the Grain Size Distribution During the Crystallization of an Amorphous Solid

2011 ◽  
Vol 1308 ◽  
Author(s):  
Andreas Bill ◽  
Ralf B. Bergmann
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Growth Rates ◽  
Amorphous Solid ◽  
Amorphous Solids ◽  
Nucleation And Growth ◽  
Analytic Description ◽  
Silicon Thin Films ◽  
Random Nucleation

ABSTRACTWe present an overview of the theory developed over the last few years to describe the crystallization of amorphous solids. The microstructure of the crystallizing solid is described in terms of the grain size distribution (GSD). We propose a partial differential equation that captures the physics of crystallization in random nucleation and growth processes. The analytic description is derived for isotropic and anisotropic growth rates and allows for the analysis of different stages of crystallization, from early to full crystallization. We show how the timedependence of effective nucleation and growth rates affect the final distribution. In particular, we demonstrate that for cases described by the Kolmogorov-Avrami-Mehl-Johnson (KAMJ) model applicable to a large class of crystallization processes a lognormal type distribution is obtained at full crystallization. The application of the theory to the crystallization of silicon thin films is discussed.

Macroscopic theory of dielectric solids. I. The model of molecular optics

1977 ◽  
Vol 55 (24) ◽  
pp. 2169-2179 ◽  
Author(s):  
J. E. Sipe
Keyword(s):  
Constitutive Relations ◽  
Pair Correlation ◽  
Finite Size ◽  
Amorphous Solid ◽  
Amorphous Solids ◽  
Uniform Density ◽  
Macroscopic Theory ◽  
Standard Result ◽  
Dielectric Solids ◽  
Spatially Varying

An improved derivation is given of the macroscopic electrodynamic equations for dielectric solids of finite size composed of molecules with a given polarizability, α = α(ω), interacting only via the retarded dipole–dipole coupling. We present a derivation of the constitutive relations for both crystalline and amorphous solids, which is not based on an expansion in powers of α, and in which the radiative reaction forces are carefully taken into account. The spatially varying density and pair correlation function of an amorphous solid, defined with the help of spatial averaging procedures, are shown to satisfy an integral 'counting' relation, which puts a condition on any physically consistent model of an amorphous solid. In the absence of dissipative damping, a medium is shown to be characterized by a real, in general spatially varying, dielectric constant. For solids of uniform density, crystalline or amorphous, we obtain the standard result that inside such a medium light propagates without scattering. For amorphous solids with varying density, the theory forms the basis of the macroscopic theory of light scattering from density in-homogeneities.

scholarly journals Photobleaching as a tool to measure the local strain field in fibrous membranes of connective tissues

2014 ◽  
Vol 10 (6) ◽  
pp. 2591-2601 ◽  
Author(s):  
C. Jayyosi ◽  
G. Fargier ◽  
M. Coret ◽  
K. Bruyère-Garnier
Keyword(s):  
Strain Field ◽  
Local Strain ◽  
Connective Tissues ◽  
Fibrous Membranes

Study on Local Strain Field Intensity Approach for Prediction Fatigue Life of Crankshaft Based on Mechanical Mechanics

2013 ◽  
Vol 644 ◽  
pp. 251-255 ◽  
Author(s):  
Ke Bao ◽  
Qiu Fang Wang ◽  
Shu Lin Liu ◽  
Zhong Liang Wei
Keyword(s):  
Field Intensity ◽  
Strain Field ◽  
Local Strain ◽  
Fatigue Tests ◽  
Bending Moments ◽  
Test Results ◽  
Life Test ◽  
Test Load ◽  
Bending Fatigue ◽  
Crack Initiation Life

The bending fatigue limit moment and crack initiation life of 4105 crankishaft in five groups of bending moments are obtained by resonant bending fatigue tests first. Then, the static finite element calculation using sub-model is performed to get the strain distributions in every test load. The results show that in the region where stress concentrate, the strain field could be seen as plane strain state. So two dimensional strain field intensity model is selected. In order to remove the influences of size and surface conditions, the radius of strain field is determined with the strain distribution under the low-life test load. After that, the local strain field intensities under each test load are calculated with the radius of strain field. Finally, the strain-life curve of material is modified by the fatigue intensity limit of crankshaft, and the predicted life agree with the test results.

Axial Strain Measurements in Skeletal Muscle at Various Strain Rates

1995 ◽  
Vol 117 (3) ◽  
pp. 262-265 ◽  
Author(s):  
T. M. Best ◽  
J. H. McElhaney ◽  
W. E. Garrett ◽  
B. S. Myers
Keyword(s):  
Skeletal Muscle ◽  
Strain Field ◽  
High Speed ◽  
Soft Tissues ◽  
Axial Strain ◽  
Local Strain ◽  
Optical Systems ◽  
Rate Dependent ◽  
Strain Formulation ◽  
Tissue Deformations

A noncontact optical system using high speed image analysis to measure local tissue deformations and axial strains along skeletal muscle is described. The spatial resolution of the system was 20 pixels/cm and the accuracy was ±0.125mm. In order to minimize the error associated with discrete data used to characterize a continuous strain field, the displacement data were fitted with a third order polynomial and the fitted data differentiated to measure surface strains using a Lagrangian finite strain formulation. The distribution of axial strain along the muscle-tendon unit was nonuniform and rate dependent. Despite a variation in local strain distribution with strain rate, the maximum axial strain, Exx = 0.614 ± 0.045 mm/mm, was rate insensitive and occurred at the failure site for all tests. The frequency response of the video system (1000 Hz) and the measurement of a continuous strain field along the entire length of the structure improve upon previous noncontact optical systems for measurement of surface strains in soft tissues.

Dislocation Core Spreading at Interfaces between Crystalline and Amorphous Solids

2001 ◽  
Vol 673 ◽  
Author(s):  
Huajian Gao ◽  
Lin Zhang ◽  
Shefford P. Baker
Keyword(s):  
Dislocation Core ◽  
Amorphous Solid ◽  
Amorphous Solids ◽  
Equilibrium Structure ◽  
Fundamental Question ◽  
Closed Form Solutions ◽  
Transmission Electron ◽  
Dependent Behavior ◽  
Amorphous Substrate ◽  
Core Width

ABSTRACTA fundamental question addressed here is concerned with the equilibrium structure of a dislocation core at an interface between a crystalline and an amorphous solid. This is motivated by experimental observations that the contrast of dislocations at an interface between a crystalline film and an amorphous substrate disappears under transmission electron microscopy. We have developed a mathematical moedl to describe the time-dependent behavior of dislocation core spreading as a function of the adhesive strength of the interface. The equilibrium core width and the rate of core spreading are determined in closed form solutions.

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