Chirality Induced by Structural Transformation in a Tensegrity: Theory and Experiment

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
Li-Yuan Zhang ◽  
Zi-Long Zhao ◽  
Qing-Dong Zhang ◽  
Xi-Qiao Feng
Keyword(s):  
Structural Transformation ◽  
Structural Parameters ◽  
Tensile Force ◽  
Plane Deformation ◽  
Deformation Mode ◽  
Critical Value ◽  
Chiral Structure ◽  
Chiral Structures ◽  
The Stability ◽  
Theory And Experiment

Chiral structures have many technologically significant applications in engineering. In this paper, we investigate, both theoretically and experimentally, the structural transformation from a symmetric X-shaped tensegrity to a chiral structure under uniaxial tension. When the applied tensile force exceeds a critical value, the initially achiral structure would exhibit snap-through buckling. At the critical state, the in-plane deformation mode of the tensegrity switches into an off-plane one. The critical condition of the structural transformation is provided in terms of structural parameters. An experiment was performed to validate the theoretical model. This work may not only deepen our understanding of the stability of tensegrities but also help design chiral structures for engineering applications.

scholarly journals Stability of nonaxisymmetric ferrofluid flow in rotating cylinders with magnetic field

2005 ◽  
Vol 2005 (23) ◽  
pp. 3727-3737 ◽  
Author(s):  
Jitender Singh ◽  
Renu Bajaj
Keyword(s):  
Magnetic Field ◽  
Applied Magnetic Field ◽  
Critical Value ◽  
Annular Space ◽  
Rotating Cylinders ◽  
The Stability

Effect of an axially applied magnetic field on the stability of a ferrofluid flow in an annular space between two coaxially rotating cylinders with nonaxisymmetric disturbances has been investigated numerically. The critical value of the ratioΩ∗of angular speeds of the two cylinders, at the onset of the first nonaxisymmetric mode of disturbance, has been observed to be affected by the applied magnetic field.

Electrohydrodynamic stability: Taylor–Melcher theory for a liquid bridge suspended in a dielectric gas

2002 ◽  
Vol 452 ◽  
pp. 163-187 ◽  
Author(s):  
C. L. BURCHAM ◽  
D. A. SAVILLE
Keyword(s):  
Surface Tension ◽  
Dielectric Constant ◽  
Electric Fields ◽  
Liquid Bridge ◽  
Numerical Solutions ◽  
Specific Conductivity ◽  
Axisymmetric Deformation ◽  
Aspect Ratios ◽  
The Stability ◽  
Theory And Experiment

A liquid bridge is a column of liquid, pinned at each end. Here we analyse the stability of a bridge pinned between planar electrodes held at different potentials and surrounded by a non-conducting, dielectric gas. In the absence of electric fields, surface tension destabilizes bridges with aspect ratios (length/diameter) greater than π. Here we describe how electrical forces counteract surface tension, using a linearized model. When the liquid is treated as an Ohmic conductor, the specific conductivity level is irrelevant and only the dielectric properties of the bridge and the surrounding gas are involved. Fourier series and a biharmonic, biorthogonal set of Papkovich–Fadle functions are used to formulate an eigenvalue problem. Numerical solutions disclose that the most unstable axisymmetric deformation is antisymmetric with respect to the bridge’s midplane. It is shown that whilst a bridge whose length exceeds its circumference may be unstable, a sufficiently strong axial field provides stability if the dielectric constant of the bridge exceeds that of the surrounding fluid. Conversely, a field destabilizes a bridge whose dielectric constant is lower than that of its surroundings, even when its aspect ratio is less than π. Bridge behaviour is sensitive to the presence of conduction along the surface and much higher fields are required for stability when surface transport is present. The theoretical results are compared with experimental work (Burcham & Saville 2000) that demonstrated how a field stabilizes an otherwise unstable configuration. According to the experiments, the bridge undergoes two asymmetric transitions (cylinder-to-amphora and pinch-off) as the field is reduced. Agreement between theory and experiment for the field strength at the pinch-off transition is excellent, but less so for the change from cylinder to amphora. Using surface conductivity as an adjustable parameter brings theory and experiment into agreement.

scholarly journals Effects of Load and Contact Time on the Stability of Bimolecular Integrin-Fibrinogen Bonds Under a Constant Tensile Force

2009 ◽  
Vol 96 (3) ◽  
pp. 595a
Author(s):  
Rustem I. Litvinov ◽  
Joel S. Bennett ◽  
John W. Weisel ◽  
Henry Shuman
Keyword(s):  
Contact Time ◽  
Tensile Force ◽  
The Stability

Numerical and Experimental Approaches to Investigate the Stability of a Motorcycle Vehicle

2006 ◽  
Author(s):  
Federico Cheli ◽  
Marco Bocciolone ◽  
Marco Pezzola ◽  
Elisabetta Leo
Keyword(s):  
Degrees Of Freedom ◽  
Structural Parameters ◽  
Experimental Tests ◽  
Roll Angle ◽  
Longitudinal Motion ◽  
Reference Trajectory ◽  
Steering Angle ◽  
Steady State Condition ◽  
The Stability ◽  
Linearized Model

The study of motorcycle’s stability is an important task for the passenger’s safety. The range of frequencies involved for the handling stability is lower than 10 Hz. A numerical model was developed to access the stability of a motorcycle vehicle in this frequency range. The stability is analysed using a linearized model around the straight steady state condition. In this condition, the vehicle’s vertical and longitudinal motion are decoupled, hence the model has only four degrees of freedom (steering angle, yaw angle, roll angle and lateral translation), while longitudinal motion is imposed. The stability was studied increasing the longitudinal speed. The input of the model can be either a driver input manoeuvre (roll angle) or a transversal component of road input able to excite the vibration modes. The driver is introduced in the model as a steering torque that allows the vehicle to follow a reference trajectory. To validate the model, experimental tests were done. To excite the vehicle modes, the driver input was not taken into account considering both the danger for the driver and the repeatability of the manoeuvre. Two different vehicle configurations were tested: vehicle 1 is a motorcycle [7] and vehicle 2 is a scooter. Through the use of the validated model, a sensitivity analysis was done changing structural (for example normal trail, steering angle, mass) and non structural parameters (for example longitudinal speed).

Notizen:Einige Bemerkungen zur Stabilität von WO2F2 / Remark on the stability of WO2F2

1978 ◽  
Vol 33 (10) ◽  
pp. 1239-1240
Author(s):  
J. de Bruijn ◽  
J. H. Dettingmeijer
Keyword(s):  
Low Temperature ◽  
Thermodynamic Data ◽  
The Stability ◽  
Equilibrium Calculations ◽  
Theory And Experiment ◽  
F System

Abstract Based on equilibrium calculations on the W-O-F system [6], in which WO2F2 was found to be the predominant low temperature species, an attempt was made to synthesize WO2F2 from WO2 + NF3.However, yields of WOF4 instead of WO2F2 were obtained. This discrepancy between theory and experiment is shown to be due to an error in the estimation of the thermodynamic data of WO2F2 [1].

The Stability of an Axially–Loaded Continuous Beam

1955 ◽  
Vol 59 (535) ◽  
pp. 506-509
Author(s):  
A. M. Dobson
Keyword(s):  
Axial Load ◽  
Classical Method ◽  
Complete Solution ◽  
Critical Value ◽  
Continuous Beam ◽  
Independent Variables ◽  
A Value ◽  
Method Of Solution ◽  
Axially Loaded ◽  
The Stability

The Classical method of solution of the stability of an axially–loaded continuous beam is by means of the three moments equation, using the Berry Functions, which are functions of the axial load. As the axial load approaches a value equal to the critical value for a pin–jointed beam, the Berry Functions tend to infinity, and the use of the three moments equations —(i. e. treating the end fixing moments as the independent variables)—leads to certain difficulties in the complete solution of the problem.The major difficulty lies in the question of stability. The critical value is determined by the vanishing of the determinant of the coefficients of the fixing moments in the three moments equations. This value could be found by plotting the determinant against end load (c. f. Pippard and Pritchard). However, in a problem involving a large number of bays, the calculation necessary to do this is likely to be considerable, for there may be many branches to the curve.

scholarly journals The assessment of the stability of the corneal structure after LASIK correction of myopia by different optical zone diameters

2016 ◽  
Vol 73 (6) ◽  
pp. 572-576 ◽  
Author(s):  
Milorad Milivojevic ◽  
Vladimir Petrovic ◽  
Miroslav Vukosavljevic ◽  
Ivan Marjanovic ◽  
Mirko Resan
Keyword(s):  
Structural Parameters ◽  
Preoperative Assessment ◽  
Laser In Situ Keratomileusis ◽  
Group I ◽  
Significant Difference ◽  
Optical Zone ◽  
Corneal Structure ◽  
The Stability ◽  
Corneal Thinning

Background/Aim. Enlargement of optical zone (OZ) diameter during laser in situ keratomileusis (LASIK) correction of myopia postoperatively improves the optical outcome, however, it also leads to the increased stroma tissue consumption - progressive corneal thinning. The aim of this investigation was to present the possibility of safe OZ enlargement without impairing the structural stability of the cornea, while obtaining an improved optical outcome with LASIK treatment of shortsightedness. Methods. Preoperative assessment of the cornea structure and prediction of the ablated stroma tissue consumption was conducted in 37 patients (74 eyes) treated for shortsightedness by means of the LASIK method. With the eyes that, according to their cornea structure, had the capacity for OZ diameter enlargement of 0.5 mm, LASIK treatment was performed within the wider OZ diameter of 7.0 mm compared to the standard 6.5 mm. The following two groups were formed, depending on the diameter of the utilized OZ: the group I (the eyes treated with the OZ 6.5 mm, n = 37) and the group II (the eyes treated with the OZ 7.0 mm, n = 37). Results. No significant difference in the observed structural parameters of the cornea was detected between the groups of patients treated with different OZ diameters. The values of all the parameters were significantly bellow the threshold values for the development of postoperative ectasia. Conclusion. Diameter enlargement of the treated OZ, if there is a preoperative cornea capacity for such enlargement, will not impair the postoperative stability of the cornea structure, and will significantly improve the optical outcome.

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