scholarly journals Force chain structure in a rod-withdrawn granular layer

2021 ◽  
pp. 2150206
Author(s):  
F. Okubo ◽  
H. Katsuragi
Keyword(s):  
Development Process ◽  
Granular Layer ◽  
Chain Structure ◽  
Force Chain ◽  
Force Chains ◽  
Clear Correlation ◽  
Total Force ◽  
Addition Formula ◽  
Systematic Analysis ◽  
Photoelastic Effect

When a rod is vertically withdrawn from a granular layer, oblique force chains can be developed by effective shearing. In this study, the force-chain structure in a rod-withdrawn granular layer was experimentally investigated using a photoelastic technique. The rod is vertically withdrawn from a two-dimensional granular layer consisting of bidisperse photoelastic disks. During the withdrawal, the development process of force chains is visualized by the photoelastic effect. By systematic analysis of photoelastic images, force chain structures newly developed by the rod withdrawing are identified and analyzed. In particular, the relation between the rod-withdrawing force [Formula: see text], total force-chains force [Formula: see text], and their average orientation [Formula: see text] are discussed. We find that the oblique force chains are newly developed by withdrawing. The force-chain angle [Formula: see text] is almost constant (approximately [Formula: see text] from the horizontal), and the total force [Formula: see text] gradually increases by the withdrawal. In addition, [Formula: see text] shows a clear correlation with [Formula: see text].

scholarly journals Topological and geometric measurements of force-chain structure

2016 ◽  
Vol 94 (3) ◽  
Author(s):  
Chad Giusti ◽  
Lia Papadopoulos ◽  
Eli T. Owens ◽  
Karen E. Daniels ◽  
Danielle S. Bassett
Keyword(s):  
Chain Structure ◽  
Force Chain

Quantitative investigation on force chain lengths during high velocity compaction of ferrous powder

2019 ◽  
Vol 33 (10) ◽  
pp. 1950113 ◽  
Author(s):  
Wei Zhang ◽  
Jian Zhou ◽  
Xuejie Zhang ◽  
Yan Zhang ◽  
Kun Liu
Keyword(s):  
High Velocity ◽  
Pearson Correlation ◽  
Quantitative Characteristic ◽  
Correlation Coefficients ◽  
High Strength ◽  
Force Chain ◽  
Force Chains ◽  
Low Probability ◽  
High Velocity Compaction ◽  
Chain Lengths

Force chains play an important role in linking the macro- and micro-mechanisms of powder in high velocity compaction (HVC). Force chain lengths, as an important quantitative characteristic, can describe the geometry of force chains. In this study, force chain lengths and their relation to other force chain characteristics in HVC were investigated by discrete element method. Results revealed that force chain length decreased and it can be related to the densification process of ferrous powder in HVC. Moreover, long force chains extended from top to bottom and may play a major role in supporting load, although the percentage of long force chains was low. Probability density functions of force chain lengths further showed the exponential decay. The proportion of short force chains increased and the proportion of long force chains decreased. Long force chains had high strength and can be aligned to the direction of the external load, but force chain lengths did not have clear relation to straightness. These relations were confirmed by Pearson correlation coefficients.

DEM Simulation on Dilatancy Phenomenon of Confined Granular Assembly under Shearing in Parallel Interface

2013 ◽  
Vol 321-324 ◽  
pp. 282-285
Author(s):  
Wei Wang ◽  
Zhan Qi Tang ◽  
Wei Gu ◽  
Kun Liu
Keyword(s):  
Particle System ◽  
Chain Structure ◽  
Force Chain ◽  
Compression Process ◽  
Dem Simulation ◽  
Granular Assembly ◽  
Panel Shear ◽  
Internal Particle ◽  
The Relationship ◽  
Parallel Interface

In order to study the dilatancy phenomenon of confined granular assembly under shearing in parallel interface, a parallel-panel shear model is constructed by discrete element method (DEM) in this paper. While the relative motion happens between the upper and lower panels, the panel and particles displacement are monitored. The expansion of upper plate and the change of particles force chain are shown. The results show that: the internal particle system keeps repeating the dilatancy and compression process, and the relationship between shear dilatancy phenomenon and force chain structure is close.

Using MR elastography to image the 3D force chain structure of a quasi-static granular assembly

2008 ◽  
Vol 11 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Lori Sanfratello ◽  
Eiichi Fukushima ◽  
Robert P. Behringer
Keyword(s):  
Chain Structure ◽  
Force Chain ◽  
Mr Elastography ◽  
Granular Assembly

scholarly journals Force chains and resonant behavior in bending of a granular layer on an elastic support

2009 ◽  
Vol 41 (6) ◽  
pp. 691-706 ◽  
Author(s):  
Kitti Rattanadit ◽  
Florin Bobaru ◽  
Konlayut Promratana ◽  
Joseph A. Turner
Keyword(s):  
Granular Layer ◽  
Elastic Support ◽  
Force Chains ◽  
Resonant Behavior

Human Engineering Analysis for the Battle Group Tactical Trainer

1983 ◽  
Vol 27 (5) ◽  
pp. 402-406
Author(s):  
Grace P. Waldrop ◽  
L. Bruce McDonald ◽  
Elizabeth Y. Lambert ◽  
L. Robert Ogus
Keyword(s):  
Human Factors ◽  
Development Process ◽  
Human Engineering ◽  
Engineering Analysis ◽  
Systematic Analysis ◽  
Analysis Process ◽  
Factors Analysis ◽  
Front End ◽  
Human Factors Analysis

Human Factors practicioners can influence and support the development process of trainers only if their recommendations are accepted and implemented. This acceptance can be enhanced by using a systematic analysis process which leads to the human factors recommendations. An initial human factors analysis is described herein which supported other front-end analyses, leading to a functonal description for the Naval Battle Group Tactical Trainer.

scholarly journals Quantitative Analysis on Force Chain of Asphalt Mixture under Haversine Loading

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Mingfeng Chang ◽  
Pingming Huang ◽  
Jianzhong Pei ◽  
Jiupeng Zhang ◽  
Binhui Zheng
Keyword(s):  
Probability Distribution ◽  
Contact Force ◽  
Performance Test ◽  
Probability Distributions ◽  
Asphalt Mixture ◽  
Force Chain ◽  
Force Chains ◽  
Angle Distribution ◽  
Laboratory Test Results ◽  
Maximum Proportion

AC-13 asphalt mixture was taken as the research object to investigate the evolution and distribution laws of force chains. A digital specimen of AC-13 asphalt mixture was reconstructed using the discrete element method (DEM) to simulate the simple performance test (SPT). Next, the force chain information among aggregate particles was extracted to analyze the evolution, probability distribution, and angle distribution of force chains. The results indicate that the AC-13 mesoscopic model reconstructed using the DEM is feasible to simulate the mesoscopic mechanical properties of asphalt mixture by comparing the predicted results and laboratory test results. The spatial distributions of force chains are anisotropic. The probability distributions of normal force chains varying with the loading times are consistent. Furthermore, the probability distribution has the maximum value at the minimum f (the ratio of contact force to mean contact force); the peak value appears again at f = 1.75 and then gradually decreases and tends to be stable. In addition, the angle distributions of force chains mainly locate near 90° and 270°, and the proportions of strong force chains are slightly greater than 50%, but the maximum proportion is only 51.12%.

scholarly journals Horizontal Transfer of Carbapenemase-Encoding Plasmids and Comparison with Hospital Epidemiology Data

2016 ◽  
Vol 60 (8) ◽  
pp. 4910-4919 ◽  
Author(s):  
C. A. Hardiman ◽  
R. A. Weingarten ◽  
S. Conlan ◽  
P. Khil ◽  
J. P. Dekker ◽  
...  
Keyword(s):  
Horizontal Transfer ◽  
Laboratory Strain ◽  
Epidemiological Data ◽  
Multidrug Resistant ◽  
Clear Correlation ◽  
Systematic Analysis ◽  
Content Type ◽  
Multiple Strains

ABSTRACTCarbapenemase-producing organisms have spread worldwide, and infections with these bacteria cause significant morbidity. Horizontal transfer of plasmids carrying genes that encode carbapenemases plays an important role in the spread of multidrug-resistant Gram-negative bacteria. Here we investigate parameters regulating conjugation using anEscherichia colilaboratory strain that lacks plasmids or restriction enzyme modification systems as a recipient and also using patient isolates as donors and recipients. Because conjugation is tightly regulated, we performed a systematic analysis of the transfer ofKlebsiella pneumoniaecarbapenemase (blaKPC)-encoding plasmids into multiple strains under different environmental conditions to investigate critical variables. We used fourblaKPC-carrying plasmids isolated from patient strains obtained from two hospitals: pKpQIL and pKPC-47e from the National Institutes of Health, and pKPC_UVA01 and pKPC_UVA02 from the University of Virginia. Plasmid transfer frequency differed substantially between different donor and recipient pairs, and the frequency was influenced by plasmid content, temperature, and substrate, in addition to donor and recipient strain. pKPC-47e was attenuated in conjugation efficiency across all conditions tested. Despite its presence in multiple clinical species, pKPC_UVA01 had lower conjugation efficiencies than pKpQIL into recipient strains. The conjugation frequency of these plasmids intoK. pneumoniaeandE. colipatient isolates ranged widely without a clear correlation with clinical epidemiological data. Our results highlight the importance of each variable examined in these controlled experiments. Thein vitromodels did not reliably predict plasmid mobilization observed in a patient population, indicating that further studies are needed to understand the most important variables affecting horizontal transferin vivo.

Medical Device Innovation Development Process

2014 ◽  
Vol 11 (04) ◽  
pp. 1450027 ◽  
Author(s):  
Yaninee Songkajorn ◽  
Natcha Thawesaengskulthai
Keyword(s):  
Medical Device ◽  
Value Creation ◽  
Development Process ◽  
Research Process ◽  
University Hospital ◽  
Innovation Development ◽  
Systematic Analysis ◽  
Synthesis Design ◽  
Process Framework

This research contributes to developing a framework for medical device innovation (MDI) development. The scope of MDI development process is based on a government university hospital. The structure of the research process taken in this paper is based on distinguishing between three empirical case studies to build a conceptual process of MDI invention. An additional case study is used to validate and test the developed model. Specifically, this MDI development process framework is composed of five main steps which are: (i) preliminary systematic analysis, (ii) risk management, (iii) MDI conceptualized design, (iv) clinical development, and (v) production and MIP marketing management. Furthermore, contributions of effective factors for implementing MDI are technological screening, interdisciplinary blending, systematic management, value creation, and synthesis design into MDI invention process.

scholarly journals Use of elastic stability analysis to explain the stress-dependent nature of soil strength

2015 ◽  
Vol 2 (4) ◽  
pp. 150038 ◽  
Author(s):  
Kevin J. Hanley ◽  
Catherine O'Sullivan ◽  
M. Ahmer Wadee ◽  
Xin Huang
Keyword(s):  
Stress Level ◽  
Frictional Resistance ◽  
Friction Angle ◽  
Underlying Mechanism ◽  
Force Chain ◽  
Force Chains ◽  
Frictional Sliding ◽  
Strong Force ◽  
Lateral Forces ◽  
Stress Dependent

The peak and critical state strengths of sands are linearly related to the stress level, just as the frictional resistance to sliding along an interface is related to the normal force. The analogy with frictional sliding has led to the use of a ‘friction angle’ to describe the relationship between strength and stress for soils. The term ‘friction angle’ implies that the underlying mechanism is frictional resistance at the particle contacts. However, experiments and discrete element simulations indicate that the material friction angle is not simply related to the friction angle at the particle contacts. Experiments and particle-scale simulations of model sands have also revealed the presence of strong force chains, aligned with the major principal stress. Buckling of these strong force chains has been proposed as an alternative to the frictional-sliding failure mechanism. Here, using an idealized abstraction of a strong force chain, the resistance is shown to be linearly proportional to the magnitude of the lateral forces supporting the force chain. Considering a triaxial stress state, and drawing an analogy between the lateral forces and the confining pressure in a triaxial test, a linear relationship between stress level and strength is seen to emerge from the failure-by-buckling hypothesis.

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