Mechanics of magnetic robots akin to soft beams supported at unanchored contacts

2021 ◽  
pp. 1-39
Author(s):  
Amanda De Oliveira Barros ◽  
Sukalyan Bhattacharya ◽  
James Yang
Keyword(s):  
Cross Section ◽  
Mathematical Theory ◽  
Numerical Scheme ◽  
Rectangular Cross Section ◽  
The Other ◽  
Theoretical Simulation ◽  
Multiple Contacts ◽  
Dimensional Parameters ◽  
Novel Algorithm ◽  
Single Contact

Abstract This article presents a novel algorithm to predict the shape and the support configurations of a magnetic robot acting like a supple beam which deforms due to an imposed magnetic field. The soft magnet loosely rests on a flat horizontal surface which provides the pivoting supports to the robot to attain its deformed shape. The key difficulty in analysis of the mechanics is the lack of any prior knowledge about the location of the contacts where the distorted beam finds support from the ground. This paper outlines an algorithm in which different possibilities referred to as modes are checked systematically to locate the placement and the nature of such supports. Consequently, the 2D shape of the soft beam can be determined without any heuristic assumption about where the magnetic robot is touching the solid surface. This work focuses on single contact sections although the algorithm idea is valid for multiple contacts as well. The mathematical theory and the numerical scheme are validated by comparing the simulated results with existing experimentally obtained configurations. Also, the parametric space of system-defining non-dimensional parameters is explored to determine when a transition happens from one mode to another, and which magnetization methods are desirable for higher stability. Through theoretical simulation the results show that a thin rectangular cross-section provides higher deformation when compared to the other two tested shapes (circular and equilateral triangle cross-section).

scholarly journals Behavior of reinforced concrete columns strenghtened by partial jacketing

2016 ◽  
Vol 9 (1) ◽  
pp. 1-21 ◽  
Author(s):  
D. B. FERREIRA ◽  
R. B. GOMES ◽  
A. L. CARVALHO ◽  
G. N. GUIMARÃES
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Concrete Columns ◽  
The Other ◽  
Self Compacting Concrete ◽  
Reinforced Concrete Columns ◽  
Compressive Stresses ◽  
Concrete Layer ◽  
Ultimate Resistance

This article presents the study of reinforced concrete columns strengthened using a partial jacket consisting of a 35mm self-compacting concrete layer added to its most compressed face and tested in combined compression and uniaxial bending until rupture. Wedge bolt connectors were used to increase bond at the interface between the two concrete layers of different ages. Seven 2000 mm long columns were tested. Two columns were cast monolithically and named PO (original column) e PR (reference column). The other five columns were strengthened using a new 35 mm thick self-compacting concrete layer attached to the column face subjected to highest compressive stresses. Column PO had a 120mm by 250 mm rectangular cross section and other columns had a 155 mm by 250mm cross section after the strengthening procedure. Results show that the ultimate resistance of the strengthened columns was more than three times the ultimate resistance of the original column PO, indicating the effectiveness of the strengthening procedure. Detachment of the new concrete layer with concrete crushing and steel yielding occurred in the strengthened columns.

Numerical Computation of Flow in Rotating Ducts

1977 ◽  
Vol 99 (1) ◽  
pp. 148-153 ◽  
Author(s):  
A. K. Majumdar ◽  
V. S. Pratap ◽  
D. B. Spalding
Keyword(s):  
Experimental Data ◽  
Kinetic Energy ◽  
Finite Difference ◽  
Numerical Computation ◽  
Cross Section ◽  
Dissipation Rate ◽  
Rectangular Cross Section ◽  
Longitudinal Direction ◽  
The Other ◽  
Constant Area

A finite-difference procedure is employed to predict the turbulent flow in ducts of rectangular cross-section, rotating about an axis normal to the longitudinal direction. The flows were treated as “parabolic” and the turbulence model used involved the solution of two differential equations, one for the kinetic energy of the turbulence and the other for its dissipation rate. Agreement with experimental data is good for a constant-area duct at low rotation, but less satisfactory for a divergent duct at larger rotation. It is argued that a “partially-parabolic” procedure will be needed to predict the latter flow correctly.

Modified Building Shapes for Reducing Vibrations of Tall Building

2013 ◽  
Vol 871 ◽  
pp. 3-8
Author(s):  
Ki Pyo You ◽  
Young Moon Kim ◽  
Jang Youl You
Keyword(s):  
Wind Tunnel ◽  
Aspect Ratio ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Damping Ratio ◽  
Tall Building ◽  
The Other ◽  
Torsional Vibrations ◽  
Side Ratio ◽  
Building Models

To investigate the aerodynamic method for reducing motion induced vortex excitation as well as the galloping and torsional flutter of a tall building, We conducted wind tunnel tests on a tall building having a rectangular cross-section with a side ratio, D/B of 4.0 and aspect ratio of 10.0. Three aeroelastic building models were constructed to assess the effect of modified building shapes on the reduction of these vibrations. One is a plain model and the others are the shape-modified versions of the plain model, in which one has chamfered corners and the other has two openings at the top level. Experimental results showed that the chamfered model was more effective than model with the opening in reducing the above-mentioned types of vibrations, especially in motion induced vortex excitation, but not in reducing torsional vibration when the reduced velocity is high. Increasing the damping ratio might not be effective in reducing the bending and torsional vibrations of both the chamfered model and the model with openings when the reduced velocity is high.

scholarly journals Linear Free Vibration Analysis of Tapered Rectangular Cantilevered Timoshenko Beams using Energy Field Meth-od

2018 ◽  
Vol 7 (4.24) ◽  
pp. 119
Author(s):  
Shaik Mahmad Raffi ◽  
Ch. Tirumala Rao
Keyword(s):  
Cross Section ◽  
Vibration Analysis ◽  
Rectangular Cross Section ◽  
Free Vibration Analysis ◽  
Field Method ◽  
Frequency Parameter ◽  
The Other ◽  
Timoshenko Beams ◽  
Energy Field ◽  
Parameter Values

Here in this paper we discuss about Energy field method. There are many methods to evaluate the natural frequency of the structures but in this research paper the authors developed a method called “Energy field method” which reduces computational efforts compared with the other methods and which is successfully applied for the Cantilever boundary condition of a tapered (rectangular cross section) Timoshenko beam and calculated the fundamental frequency parameter values and compared the results with existing literature. To confirm the precision, coherence and adaptability of the model these resultant values are also compared with modal structural analysis values in Ansys10 software.

scholarly journals Measurements of the absolute indices of refraction in strained glass

1910 ◽  
Vol 83 (566) ◽  
pp. 572-579 ◽  
Keyword(s):  
Plane Wave ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Vertical Plane ◽  
Bending Moment ◽  
The Other ◽  
Double Refraction ◽  
Light Passing ◽  
The Absolute ◽  
The Cross

1. In June, 1907, the author described a method by which the double-refraction in strained glass could be measured by observing the deviation of a ray of light passing through a slab of glass under flexure. If a slab or beam of glass of rectangular cross-section be bent in a vertical plane under a bending moment M, and if a plane wave be transmitted through the glass in a direction perpendicular to the plane of flexure, the light is broken up into two components, one polarised horizontally ( i. e . perpendicular to the cross-section and along the line of stress) and the other vertically.

scholarly journals INFLUENCE OF GATE SHAPE AND DIRECTION DURING CENTRIFUGAL CASTING ON ARTIFICIAL LUMBAR DISC MODEL OF CP-TI

2019 ◽  
Vol 25 (3) ◽  
pp. 193
Author(s):  
Lilik Dwi Setyana ◽  
Muslim Mahardika ◽  
Sutiyoko Sutiyoko ◽  
Suyitno Suyitno
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Lumbar Disc ◽  
Centrifugal Casting ◽  
Circular Cross Section ◽  
The Other ◽  
Oblique Direction ◽  
Disc Model ◽  
Cp Ti

<p class="AMSmaintext">Shape and direction of gate in centrifugal casting affected the microstructures and defects in castings. The purpose of this research was to determine the effects of gate shape and direction in centrifugal casting toward on porosity, density, roughness, and microstructures on the artificial lumbar disc model. The main shapes of the gate were circular and rectangular cross-section.  The circular cross-section gate shape was used for two different directions of artificial lumbar discs; vertical, and horizontal. Furthermore, the rectangular cross-section gate shape consisted of three different directions; oblique clockwise, oblique counter-clockwise and perpendicular towards the mold. The rotational mold was conducted at a speed of 60 rpm. The results showed that the rectangular cross-section gate shape with the oblique direction same with the rotation of the mold produced artificial lumbar disc model that had the smallest porosity area among the other directions. It was the best shape and direction of the gate among the others which had the smallest porosity area (0,68%), highest density (4,517 g/cm<sup>3</sup>), and smoothest roughness (8,76 µm). In the sub-surface, the microstructure of α-case was formed. The thickness and hardness of the α-case in this design were 50-100 µm and 760 VHN, respectively. Hence, the rectangular cross-section gate shape with the oblique direction same with the rotation of the mold was appropriate to be applied in the manufacture of an artificial lumbar disc model.</p>

Analysis of the Collapse Behaviour Regarding TWB Crash-Boxes in Conjunction with the Construction Technique

2014 ◽  
Vol 657 ◽  
pp. 634-638
Author(s):  
Vlad Andrei Ciubotariu
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Weld Line ◽  
Maximum Level ◽  
The Other ◽  
Construction Technique ◽  
Tailor Welded Blanks ◽  
Thin Walled Structures ◽  
The Mean ◽  
Thin Walled

The crash-boxes are thin-walled structural components with rectangular cross-section which are utilized in the construction of the resistance body structures in the auto industry. This components can be manufactured from various materials including homogenous steel sheet metals, tailor welded blanks (TWB) or even composite materials. The benefits of using TWB were shown in numerous studies before and they are not the main purpose here.This research focuses on the collapse behaviour of TWB thin-walled structures with rectangular cross-section subject of impact loadings. The main objective is to design a crash-box which allows the absorption and dissipation of great kinetic energy constituting better resistance structures for car bodies.After analysing the resulted data, a few aspects regarding the TWB crash-boxes were revealed and some conclusions could be suggested: the weld line generates a barrier like zone which delays in some manner the propagation of the progressive buckling levelling the mean crash load; no flange crash-boxes presented best results regarding the mean crash load even if the data were very close to the other crash-box types. Furthermore, the peak crash load was at maximum level comparing with the other crash-box types. This collapsing behaviour of the no flange crash-boxes could be assigned to the fact that the bonded sides of the structure work like double walls into the same cress-section and is not really affecting the asymmetric crash mode of the structure.

The Fundamental Flexural Vibration of a Cantilever Beam of Rectangular Cross Section with Uniform Taper

1965 ◽  
Vol 16 (2) ◽  
pp. 139-144 ◽  
Author(s):  
J. S. Rao
Keyword(s):  
Galerkin Method ◽  
Natural Frequency ◽  
Cantilever Beam ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Flexural Vibration ◽  
The Other ◽  
Correction Factors ◽  
Flexural Mode ◽  
The Galerkin Method

SummaryAn attempt has been made to determine the natural frequency of fundamental flexural mode of a cantilever beam with uniform taper by the Galerkin method. The method suggested considerably reduces the calculations as compared with the other methods available and the results are checked with the correction factors derived by Martin.

Nonlinear mechanics of fluidization of beds of spherical particles

1987 ◽  
Vol 177 ◽  
pp. 467-483 ◽  
Author(s):  
A. F. Fortes ◽  
D. D. Joseph ◽  
T. S. Lundgren
Keyword(s):  
Cross Section ◽  
Rectangular Cross Section ◽  
Two Dimensions ◽  
The Other ◽  
Three Dimensions ◽  
Spherical Particles ◽  
Inertial Effects ◽  
Nonlinear Mechanics ◽  
Clear Water ◽  
Cooperative Motion

Experiments on fluidization with water of spherical particles falling against gravity in columns of rectangular cross-section are described. All of them are dominated by inertial effects associated with wakes. Two local mechanisms are involved: drafting and kissing and tumbling into stable cross-stream arrays. Drafting, kissing and tumbling are rearrangement mechanisms in which one sphere is captured in the wake of the other. The kissing spheres are aligned with the stream. The streamwise alignment is massively unstable and the kissing spheres tumble into more stable cross-stream pairs of doublets which can aggregate into larger relatively stable horizontal arrays. Cross-stream arrays in beds of spheres constrained to move in two dimensions are remarkable. These arrays may even coalesce into aggregations of close-packed spheres separated by regions of clear water. A somewhat weaker form of cooperative motion of cross-stream arrays of rising spheres is found in beds of square cross-section where the spheres may move freely in three dimensions. Horizontal arrays rise where drafting spheres fall because of greater drag. Aggregation of spheres seems to be associated with relatively stable cooperative motions of horizontal arrays of spheres rising in their own wakes.

scholarly journals AN EXPERIMENTAL INVESTIGATION OF STATIC PRESSURE DISTRIBUTIONS ON A GROUP OF SQUARE OR RECTANGULAR CYLINDERS WITH ROUNDED CORNERS

1970 ◽  
Vol 41 (1) ◽  
pp. 42-49 ◽  
Author(s):  
A.C. Mandal ◽  
G. M. G. Faruk
Keyword(s):  
Cross Section ◽  
Static Pressure ◽  
Rectangular Cross Section ◽  
Flow Direction ◽  
Tall Buildings ◽  
Wind Load ◽  
Open Circuit ◽  
The Other ◽  
Appreciable Effect ◽  
Pressure Distributions

The static pressure distributions on a group of cylinders with either square or rectangular cross-section having rounded corners are presented. The test is conducted at the exit end of an open circuit wind tunnel with uniform velocity of 14.2 m/s across the cylinder with Reynolds number of 2.87 x 104 and 4.20 x 104 based on the side dimension of the cylinder normal to the direction of the approach flow. The experiment is performed for a group consisting of two cylinders one behind the other along the flow direction with different side dimensions at zero angle of attack for various interspacing between the cylinders. It is observed from the experimental results that there is appreciable effect of the side dimension and interspacing on the drag coefficient of the cylinders. The results are applicable to a group consisting of two tall buildings one behind the other along the wind velocity direction and each building of either square or rectangular cross-section having rounded corners. The wind load on the downstream cylinder decreases remarkably due to the presence of the cylinder in the upstream side.Keywords: Wind load; Group of buildings.DOI: 10.3329/jme.v41i1.5361Journal of Mechanical Engineering, Vol. ME 41, No. 1, June 2010 42-49

Sign in / Sign up

Export Citation Format

Share Document