scholarly journals Interparticle attraction controls flow heterogeneity in calcite gels

Soft Matter ◽  
2020 ◽  
Vol 16 (40) ◽  
pp. 9217-9229
Author(s):  
Teresa Liberto ◽  
Marie Le Merrer ◽  
Sébastien Manneville ◽  
Catherine Barentin
Keyword(s):  
Shear Bands ◽  
Colloidal Gels ◽  
Flow Heterogeneity ◽  
Temporal Fluctuations

Increasing interparticle attraction in calcite colloidal gels leads to flow heterogeneities including shear bands and temporal fluctuations.

Analysis of shear bands in slow granular flows using a frictional Cosserat model

2000 ◽  
Vol 627 ◽  
Author(s):  
Prabhu R. Nott ◽  
K. Kesava Rao ◽  
L. Srinivasa Mohan
Keyword(s):  
Scaling Laws ◽  
Shear Bands ◽  
Shear Layers ◽  
Theoretical Description ◽  
Field Variable ◽  
Cosserat Continuum ◽  
Momentum Balance ◽  
Rigid Plastic ◽  
Independent Field ◽  
Cosserat Model

ABSTRACTThe slow flow of granular materials is often marked by the existence of narrow shear layers, adjacent to large regions that suffer little or no deformation. This behaviour, in the regime where shear stress is generated primarily by the frictional interactions between grains, has so far eluded theoretical description. In this paper, we present a rigid-plastic frictional Cosserat model that captures thin shear layers by incorporating a microscopic length scale. We treat the granular medium as a Cosserat continuum, which allows the existence of localised couple stresses and, therefore, the possibility of an asymmetric stress tensor. In addition, the local rotation is an independent field variable and is not necessarily equal to the vorticity. The angular momentum balance, which is implicitly satisfied for a classical continuum, must now be solved in conjunction with the linear momentum balances. We extend the critical state model, used in soil plasticity, for a Cosserat continuum and obtain predictions for flow in plane and cylindrical Couette devices. The velocity profile predicted by our model is in qualitative agreement with available experimental data. In addition, our model can predict scaling laws for the shear layer thickness as a function of the Couette gap, which must be verified in future experiments. Most significantly, our model can determine the velocity field in viscometric flows, which classical plasticity-based model cannot.

The Effect of Secondary Metalworking Processes on Susceptibility of Aircraft to Catastrophic Failures and Prevention Methods

2013 ◽  
Vol 58 (4) ◽  
pp. 1207-1212
Author(s):  
E.S. Dzidowski
Keyword(s):  
Dynamic Recovery ◽  
Fatigue Cracks ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Deformation Mechanisms ◽  
Processing Maps ◽  
Adiabatic Shear Bands ◽  
Flow Localization ◽  
Catastrophic Failures ◽  
Prevention Methods

Abstract The causes of plane crashes, stemming from the subcritical growth of fatigue cracks, are examined. It is found that the crashes occurred mainly because of the negligence of the defects arising in the course of secondary metalworking processes. It is shown that it is possible to prevent such damage, i.e. voids, wedge cracks, grain boundary cracks, adiabatic shear bands and flow localization, through the use of processing maps indicating the ranges in which the above defects arise and the ranges in which safe deformation mechanisms, such as deformation in dynamic recrystallization conditions, superplasticity, globularization and dynamic recovery, occur. Thanks to the use of such maps the processes can be optimized by selecting proper deformation rates and forming temperatures.

Self-Heating of Polyethylene Terephthalate in Shear Bands

2020 ◽  
Vol 492 (1) ◽  
pp. 57-59
Author(s):  
S. L. Bazhenov ◽  
I. V. Sosnovskii ◽  
A. S. Kechek’yan
Keyword(s):  
Polyethylene Terephthalate ◽  
Shear Bands ◽  
Self Heating

Role of temporal fluctuations of laser radiation intensity in studies of statistical behaviour of lasher damage associated with absorbing inclusions

1994 ◽  
Vol 24 (11) ◽  
pp. 1000-1002
Author(s):  
M F Koldunov ◽  
Aleksandr A Manenkov ◽  
I L Pokotilo
Keyword(s):  
Laser Radiation ◽  
Radiation Intensity ◽  
Laser Radiation Intensity ◽  
Temporal Fluctuations

scholarly journals Ecological drift and competitive interactions predict unique patterns in temporal fluctuations of population size

Ecology ◽  
2019 ◽  
Vol 100 (4) ◽  
pp. e02623 ◽  
Author(s):  
Werner Ulrich ◽  
Radosław Puchałka ◽  
Marcin Koprowski ◽  
Giovanni Strona ◽  
Nicholas J. Gotelli
Keyword(s):  
Population Size ◽  
Competitive Interactions ◽  
Temporal Fluctuations ◽  
Ecological Drift

scholarly journals An Insight into Amorphous Shear Band in Magnetorheological Solid by Atomic Force Microscope

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4384
Author(s):  
Mohd Aidy Faizal Johari ◽  
Asmawan Mohd Sarman ◽  
Saiful Amri Mazlan ◽  
Ubaidillah U ◽  
Nur Azmah Nordin ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Shear Band ◽  
Shear Bands ◽  
Test Duration ◽  
Phase Imaging ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Matrix ◽  
Relaxation Stress ◽  
Band Deformation

Micro mechanism consideration is critical for gaining a thorough understanding of amorphous shear band behavior in magnetorheological (MR) solids, particularly those with viscoelastic matrices. Heretofore, the characteristics of shear bands in terms of formation, physical evolution, and response to stress distribution at the localized region have gone largely unnoticed and unexplored. Notwithstanding these limitations, atomic force microscopy (AFM) has been used to explore the nature of shear band deformation in MR materials during stress relaxation. Stress relaxation at a constant low strain of 0.01% and an oscillatory shear of defined test duration played a major role in the creation of the shear band. In this analysis, the localized area of the study defined shear bands as varying in size and dominantly deformed in the matrix with no evidence of inhibition by embedded carbonyl iron particles (CIPs). The association between the shear band and the adjacent zone was further studied using in-phase imaging of AFM tapping mode and demonstrated the presence of localized affected zone around the shear band. Taken together, the results provide important insights into the proposed shear band deformation zone (SBDZ). This study sheds a contemporary light on the contentious issue of amorphous shear band deformation behavior and makes several contributions to the current literature.

scholarly journals Numerical simulation of adiabatic shear bands formation processes on two-dimensional eulerian meshes

2020 ◽  
Vol 1686 ◽  
pp. 012035
Author(s):  
R V Muratov ◽  
N A Kudryashov ◽  
P N Ryabov
Keyword(s):  
Numerical Simulation ◽  
Shear Bands ◽  
Adiabatic Shear ◽  
Formation Processes ◽  
Two Dimensional ◽  
Adiabatic Shear Bands

Taking a Deep Dive Into The Batteryless Internet of Things With Shepherd

2021 ◽  
Vol 24 (3) ◽  
pp. 5-8
Author(s):  
Kai Geissdoerfer ◽  
Mikołaj Chwalisz ◽  
Marco Zimmerling
Keyword(s):  
Energy Storage ◽  
Internet Of Things ◽  
Sensor Nodes ◽  
Energy Availability ◽  
Deep Dive ◽  
Temporal Fluctuations ◽  
Temporal Characteristics ◽  
Challenges And Opportunities ◽  
Spatio Temporal

Collaboration of batteryless devices is essential to their success in replacing traditional battery-based systems. Without significant energy storage, spatio-temporal fluctuations of ambient energy availability become critical for the correct functioning of these systems. We present Shepherd, a testbed for the batteryless Internet of Things (IoT) that can record and reproduce spatio-temporal characteristics of real energy environments to obtain insights into the challenges and opportunities of operating groups of batteryless sensor nodes.

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