scholarly journals The structural, vibrational, and mechanical properties of jammed packings of deformable particles in three dimensions

Soft Matter ◽  
2021 ◽  
Author(s):  
Dong Wang ◽  
John Treado ◽  
Arman Boromand ◽  
Blake Norwick ◽  
Michael Murrell ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Degrees Of Freedom ◽  
Three Dimensions ◽  
Deformable Particles ◽  
Deformable Particle

We investigate the structural, vibrational, and mechanical properties of jammed packings of deformable particles with shape degrees of freedom in three dimensions (3D). Each 3D deformable particle is modeled as...

scholarly journals BIOMIMETIC DESIGN OF LOW STIFFNESS ACTUATOR SYSTEMS FOR PROSTHETIC LIMBS

2011 ◽  
Author(s):  
D. L. Russell ◽  
M. McTavish
Keyword(s):  
Mechanical Properties ◽  
Degrees Of Freedom ◽  
Analytical Techniques ◽  
Energetic Costs ◽  
Multiple Degrees Of Freedom ◽  
Prosthetic Limbs ◽  
Limb Stiffness ◽  
Human Arm ◽  
Biomimetic Approach ◽  
Low Stiffness

The various relationships that are possible between the mechanical properties of single actuators and the overall mechanism (in this case a human arm with or without a prosthetic elbow) are discussed. Graphical and analytical techniques for describing the range of overall limb stiffnesses that are achievable and for characterizing the overall limb stiffness have been developed. Using a biomimetic approach and, considering energetic costs, stability and complexity, the implications of choosing passive or active implementations of stiffness are discussed. These techniques and approaches are particularly applicable with redundant (agonist - antagonist) actuators and multiple degrees of freedom. Finally, a novel biomimetic approach for control is proposed.

Research on Simulation Customers Participate Type in Open Innovation

2014 ◽  
Vol 926-930 ◽  
pp. 2054-2057
Author(s):  
Jun Hui He
Keyword(s):  
Open Innovation ◽  
Degrees Of Freedom ◽  
New Products ◽  
Innovation Process ◽  
Degree Of Freedom ◽  
Three Dimensions ◽  
Dynamic Evolution ◽  
Evolution Simulation ◽  
High Degree

This paper proposed customers to participate typology based on three dimensions, which are the customers’ autonomy in the process, the nature of the firm‐customer collaboration, and the stage of the innovation process. Then proposed customers to participate in the type of open innovation framework. Through the static comparative and dynamic evolution simulation found: customers tend to be open to participate in the development of new products pre innovation, the tendency to begin to choose the low participation of degrees of freedom, and ultimately tend to opt for a high degree of freedom to participate.

Monkey superior colliculus represents rapid eye movements in a two-dimensional motor map

1993 ◽  
Vol 69 (3) ◽  
pp. 965-979 ◽  
Author(s):  
K. Hepp ◽  
A. J. Van Opstal ◽  
D. Straumann ◽  
B. J. Hess ◽  
V. Henn
Keyword(s):  
Eye Movements ◽  
Superior Colliculus ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Eye Position ◽  
Two Dimensional ◽  
Vestibular Nystagmus ◽  
Rapid Eye Movements ◽  
Q Model

1. Although the eye has three rotational degrees of freedom, eye positions, during fixations, saccades, and smooth pursuit, with the head stationary and upright, are constrained to a plane by ListingR's law. We investigated whether Listing's law for rapid eye movements is implemented at the level of the deeper layers of the superior colliculus (SC). 2. In three alert rhesus monkeys we tested whether the saccadic motor map of the SC is two dimensional, representing oculocentric target vectors (the vector or V-model), or three dimensional, representing the coordinates of the rotation of the eye from initial to final position (the quaternion or Q-model). 3. Monkeys made spontaneous saccadic eye movements both in the light and in the dark. They were also rotated about various axes to evoke quick phases of vestibular nystagmus, which have three degrees of freedom. Eye positions were measured in three dimensions with the magnetic search coil technique. 4. While the monkey made spontaneous eye movements, we electrically stimulated the deeper layers of the SC and elicited saccades from a wide range of initial positions. According to the Q-model, the torsional component of eye position after stimulation should be uniquely related to saccade onset position. However, stimulation at 110 sites induced no eye torsion, in line with the prediction of the V-model. 5. Activity of saccade-related burst neurons in the deeper layers of the SC was analyzed during rapid eye movements in three dimensions. No systematic eye-position dependence of the movement fields, as predicted by the Q-model, could be detected for these cells. Instead, the data fitted closely the predictions made by the V-model. 6. In two monkeys, both SC were reversibly inactivated by symmetrical bilateral injections of muscimol. The frequency of spontaneous saccades in the light decreased dramatically. Although the remaining spontaneous saccades were slow, Listing's law was still obeyed, both during fixations and saccadic gaze shifts. In the dark, vestibularly elicited fast phases of nystagmus could still be generated in three dimensions. Although the fastest quick phases of horizontal and vertical nystagmus were slower by about a factor of 1.5, those of torsional quick phases were unaffected. 7. On the basis of the electrical stimulation data and the properties revealed by the movement field analysis, we conclude that the collicular motor map is two dimensional. The reversible inactivation results suggest that the SC is not the site where three-dimensional fast phases of vestibular nystagmus are generated.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals ENTROPY AND AREA IN LOOP QUANTUM GRAVITY

2005 ◽  
Vol 14 (12) ◽  
pp. 2301-2305
Author(s):  
JOHN SWAIN
Keyword(s):  
Black Hole ◽  
Quantum Gravity ◽  
Maximum Entropy ◽  
Degrees Of Freedom ◽  
Loop Quantum Gravity ◽  
Black Hole Entropy ◽  
Black Hole Thermodynamics ◽  
Three Dimensions ◽  
Spin Network

Black hole thermodynamics suggests that the maximum entropy that can be contained in a region of space is proportional to the area enclosing it rather than its volume. We argue that this follows naturally from loop quantum gravity and a result of Kolmogorov and Bardzin' on the the realizability of networks in three dimensions. This represents an alternative to other approaches in which some sort of correlation between field configurations helps limit the degrees of freedom within a region. It also provides an approach to thinking about black hole entropy in terms of states inside rather than on its surface. Intuitively, a spin network complicated enough to imbue a region with volume only lets that volume grow as quickly as the area bounding it.

scholarly journals Compressible Flow Simulation with Moving Geometries using the Brinkman Penalization in High-Order Discontinuous Galerkin

2020 ◽  
Author(s):  
Neda Ebrahimi Pour ◽  
Nikhil Anand ◽  
Harald Klimach ◽  
Sabine Roller
Keyword(s):  
Degrees Of Freedom ◽  
Flow Simulation ◽  
High Order ◽  
Three Dimensions ◽  
Limiting Factor ◽  
Moving Wall ◽  
Low Dissipation ◽  
Computational Mesh ◽  
Penalization Technique ◽  
Discontinous Galerkin

Abstract In this work we investigate the Brinkman volume penalization technique in the context of a high-order Discontinous Galerkin method to model moving wall boundaries for compressible fluid flow simulations. High-order approximations are especially of interest as they require few degrees of freedom to represent smooth solutions accurately. This reduced memory consumption is attractive on modern computing systems where the memory bandwidth is a limiting factor. Due to their low dissipation and dispersion they are also of particular interest for aeroacoustic problems. However, a major problem for the high-order discretization is the appropriate representation of wall geometries. In this work we look at the Brinkman penalization technique, which addresses this problem and allows the representation of geometries without modifying the computational mesh. The geometry is modelled as an artificial porous medium and embedded in the equations. As the mesh is independent of the geometry with this method, it is not only well suited for highorder discretizations but also for problems where the obstacles are moving.We look into the deployment of this strategy by briefly discussing the Brinkman penalization technique and its application in our solver and investigate its behavior in fundamental one-dimensional setups, such as shock reflection at a moving wall and the formation of a shock in front of a piston. This is followed by the application to setups with two and three dimensions, illustrating the method in the presence of curved surfaces.

scholarly journals VIRTUAL LABORATORIES AS STRATEGY FOR TEACHING IMPROVEMENT IN MATH SCIENCES AND ENGINEERING IN BOLIVIA

2020 ◽  
Vol 2 (1) ◽  
pp. 52-62
Author(s):  
Francisco Vargas
Keyword(s):  
Differential Equations ◽  
Matrix Algebra ◽  
Degrees Of Freedom ◽  
Inverted Pendulum ◽  
Numerical Algorithms ◽  
Three Dimensions ◽  
Technological Advancement ◽  
Teaching Improvement ◽  
Two Degrees Of Freedom ◽  
Virtual Laboratories

The vertiginous technological advancement has made necessary the use of computersoftware that contributes to the improvement of teaching in math sciences and engineering.It is in this context that the last five years the strategy presented in this article has been disseminatedin the main universities of Bolivia, a country where the schools have not yet been ableto offer basic disciplines such as calculus, matrix algebra, physics and/or differential equationsto solve problems considering applicative aspects. To establish this connection, it is necessaryto deduce differential equations associated with practical problems, solve these equationswith different numerical algorithms, and establish the concept of simulation to later introducelanguages like Python/VPython free of license to elaborate Virtual Laboratories that allow obtainingthe solutions in two and three dimensions. The classical problems addressed for thispurpose are the satellite of two degrees of freedom and the inverted pendulum.

THREE-DIMENSIONAL COSSERAT CONTINUUM MODELING OF FRACTURED ROCK MASSES

2010 ◽  
Vol 02 (03n04) ◽  
pp. 217-234
Author(s):  
IOANNIS STEFANOU ◽  
JEAN SULEM
Keyword(s):  
Mechanical Properties ◽  
Discrete System ◽  
Degrees Of Freedom ◽  
Fractured Rock ◽  
Three Dimensional ◽  
Cosserat Continuum ◽  
Point Of View ◽  
Rock Masses ◽  
Homogenization Technique ◽  
Rock Structure

The behavior of rock masses is influenced by the existence of discontinuities, which divide the rock in joint blocks making it an inhomogeneous anisotropic material. From the mechanical point of view, the geometrical and mechanical properties of the rock discontinuities define the mechanical properties of the rock structure. In the present paper we consider a rock mass with three joint sets of different dip angle, dip direction, spacing and mechanical properties. The dynamic behavior of the discrete system is then described by a continuum model, which is derived by homogenization. The homogenization technique applied here is called generalized differential expansion homogenization technique and has its roots in Germain's (1973) formulation for micromorphic continua. The main advantage of the method is the avoidance of the averaging of the kinematic quotients and the derivation of a continuum that maps exactly the degrees of freedom of the discrete system through a one-to-one correspondence of the kinematic measures. The derivation of the equivalent continuum is based on the identification for any virtual kinematic field of the power of the internal forces and of the kinetic energy of the continuum with the corresponding quantities of the discrete system. The result is an anisotropic three-dimensional Cosserat continuum.

Three-Dimensional Nonlinear Dynamics of Nonintegral Riser Bundle

1991 ◽  
Vol 35 (01) ◽  
pp. 40-57
Author(s):  
Nickolas Vlahopoulos ◽  
Michael M. Bernitsas
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Small Strain ◽  
Computer Code ◽  
Three Dimensions ◽  
Central Processor ◽  
Beam Columns ◽  
Central Processor Unit ◽  
Processor Unit ◽  
Strain Model

The dynamic behavior of a nonintegral riser bundle is studied parametrically. The dynamics of each component-riser is analyzed by a three-dimensional, nonlinear, large deflection, small strain model with coupled bending and torsion. Component-risers are slender, thin-walled, extensible or inextensible tubular beam-columns, subject to response and deformation dependent hydrodynamic loads. The con-nector equations of equilibrium are used to derive the connector forces and moments. Substructuring can thus be achieved even though in three dimensions connectors do not impose linearly dependent deflections at substructure interfaces. The developed time incremental and iterative finite-element computer code is used to analyze the effects of water depth, distribution of connectors, distance between component risers and number of finite elements in the numerical model. The problem of total CPU (central processor unit) time and the advantages of substructuring are discussed by running cases of up to 1094 degrees of freedom.

Microstructures and Mechanical Properties of Mg Alloy FSW Joint Characterized with Asymmetric Gradient in Three Dimension

2013 ◽  
Vol 749 ◽  
pp. 180-186
Author(s):  
Sheng Lu ◽  
Dai Li Yang ◽  
Shi Yu Xiao ◽  
Ali Lu
Keyword(s):  
Mechanical Properties ◽  
Temperature Distribution ◽  
Longitudinal Direction ◽  
Three Dimensions ◽  
Welding Parameters ◽  
Three Dimension ◽  
Friction Stir ◽  
Microhardness Distribution ◽  
The One ◽  
Fsw Experiments

Friction stir welding (FSW) experiments were carried out on AZ31 magnesium alloy under the optimized welding parameters. The temperature distribution, macrostructure and microstructure, mechanical properties of the joint were studied along three dimensions (transverse direction, longitudinal direction, thickness direction). Temperature distribution, joint appearance and microstructure demonstrate asymmetric gradient in three dimensions. The peak temperature of featured points at the welding beginning stage was lower, and the one in the ending stage was higher. The temperature of advancing side was higher than that of the retreating side. More in detail, the dynamically recrystallized microstructure in weld nugget zone (WNZ) was uniform and small. The thermomechanically affected zones (TMAZ) closed to the WNZ, which were characterized with bended and elongated grains. At advancing side, the interface between TMAZ and WNZ was very distinct. The microhardness distribution showed a typical W shape. The profile showed a slightly lower hardness in the WNZ than in the base metal,HAZ, and TMAZ correspond to the lowest one. The FSW joints were observed to fail mostly at the boundary between WNZ and TMAZ at the advancing side.

Preliminary Study of Manufacturing Technique Using Three Dimensions Stain Steel Braid for Bone Scaffold

2012 ◽  
Vol 184-185 ◽  
pp. 1424-1427
Author(s):  
Jia Horng Lin ◽  
Ching Wen Lin ◽  
Yueh Sheng Chen ◽  
Chien Lin Huang ◽  
Wen Cheng Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Stress Shielding ◽  
Three Dimensions ◽  
304 Stainless Steel ◽  
Shielding Effect ◽  
Metallic Materials ◽  
Bone Scaffold ◽  
Artificial Bone ◽  
Stereo Microscope

Nowadays, as rising research on biomaterials, the artificial bone scaffold has become the most important part of the study. Moreover, metallic materials have been applied on the artificial bone scaffold; but its high rigidity causes the stress shielding effect in bones. To improve the disadvantages of metallic materials and pursue their better mechanical properties, 304 stainless steel fibers have multi-layer braided into the 3D stainless-steel braid with porous structure and better mechanical properties, using braiding machine. In multi-layer braiding process, with the constant number of take-up gear and varying number of braid gear, the 3D stainless-steel braid was manufactured. Afterwards, its braiding structure and angle were observed by stereo microscope. Also, the optimal braiding parameters can be acquired from tensile strength test.

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