A Computational Study of Insect Wing Cross-Sectional Geometry on Flight Performance

2015 ◽  
Author(s):  
Jeffrey Feaster ◽  
Francine Battaglia ◽  
Javid Bayandor
Keyword(s):  
Cross Section ◽  
Degrees Of Freedom ◽  
Insect Flight ◽  
Computational Study ◽  
Flight Performance ◽  
Cross Sectional ◽  
Insect Wing ◽  
Agile Flight ◽  
Robotic Applications ◽  
Three Degrees Of Freedom

The influence of cross-sectional geometry on flight performance is investigated for an insect wing using bee-like kinematics. Bee flight is of particular interest due to its mechanical simplicity, utilizing only three degrees of freedom, a high flap frequency, and mechanically linked front and hind wings. These unique flapping flight kinematics result in extremely agile flight characteristics, capable of carrying extraordinary loads relative to the bee’s weight, at a biologically capable efficiency. The performance of a corrugated insect wing and a more intuitively aerodynamic profile are compared computationally. At velocities from 1–3 m/s, the approximated cross-section is foudn to overpredict the lift generated by the corrugated profile by up to 18%. At higher velocities, 4 and 5 m/s, the approximated profile underpredicts the lift generated by the corrugated cross-section by 15%. Based upon this information the cross-sectional geometry of an insect’s wing is significant to the investigation and quantification of insect flight characteristics, for both computational analysis and future robotic applications.

scholarly journals On the shape of cicada’s wing leading-edge cross section

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rachel M. Starkweather ◽  
Svetlana V. Poroseva ◽  
David T. Hanson
Keyword(s):  
Cross Section ◽  
Insect Flight ◽  
Leading Edge ◽  
Flight Performance ◽  
Cross Section Shape ◽  
Section Shape ◽  
First Time

AbstractAn important role that the leading-edge cross-section shape plays in the wing flight performance is well known in aeronautics. However, little is known about the shape of the leading-edge cross section of an insect’s wing and its contribution to remarkable qualities of insect flight. In this paper, we reveal, in the first time, the shape of the leading-edge cross section of a cicada’s wing and analyze its variability along the wing. We also identify and quantify similarities in characteristic dimensions of this shape in the wings of three different cicada species.

scholarly journals Coupled Bending-Bending-Torsion Vibration of a Pre-Twisted Beam with Aerofoil Cross-Section by the Finite Element Method

2003 ◽  
Vol 10 (4) ◽  
pp. 223-230
Author(s):  
Bulent Yardimoglu ◽  
Daniel J. Inman
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Higher Order ◽  
Coupling Coefficients ◽  
Cross Sectional ◽  
Torsion Vibration ◽  
Proper Order ◽  
Proposed Model

The present study deals with a finite element model for coupled bending-bending-torsion vibration analysis of a pretwisted Timoshenko beam with varying aerofoil cross-section. The element derived in this paper has two nodes, with seven degrees of freedom at each node. The nodal variables are transverse displacements, cross-section rotations and the shear angles in two planes and torsional displacement. The advantage of the present element is the exclusion of unnecessary derivatives of fundamental nodal variables, which were included to obtain invertable square matrix by other researchers, by choosing proper displacement functions and using relationship between cross-sectional rotation and the shear deformation. Element stiffness and mass matrices are developed from strain and kinetic energy expressions by assigning proper order polynomial expressions for cross-section properties and considering higher order coupling coefficients. The correctness of the present model is confirmed by the experimental results available in the literature. Comparison of the proposed model results with those in the literature indicates that a faster convergence is obtained. The results presented also provide some insights in the formulation by clearly indicating that higher order coupling terms have considerable influence on the natural frequencies.

Utilization of Cable Guide Channels for Compact Articulation Within a Dexterous Three Degrees-of-Freedom Surgical Wrist Design

2018 ◽  
Vol 13 (1) ◽  
Author(s):  
Dale J. Podolsky ◽  
Eric Diller ◽  
David M. Fisher ◽  
Karen W. Wong Riff ◽  
Thomas Looi ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Small Body ◽  
Body Cavity ◽  
Cable Tension ◽  
Actuation Mechanism ◽  
3D Printed ◽  
Path Lengths ◽  
Three Degree Of Freedom ◽  
Robotic Applications ◽  
Three Degrees Of Freedom

Pin-jointed wrist mechanisms provide compact articulation for surgical robotic applications, but are difficult to miniaturize at scales suitable for small body cavity surgery. Solid surface cable guide channels, which eliminate the need for pulleys and reduce overall length to facilitate miniaturization, were developed within a three-degree-of-freedom cable-driven pin-jointed wrist mechanism. A prototype was 3D printed in steel at 5 mm diameter. Friction generated by the guide channels was experimentally tested to determine increases in cable tension during constant cable velocity conditions. Cable tension increased exponentially from 0 to 37% when the wrist pitched from 0 deg to 90 deg. The shape of the guide channel groove and angle, where the cable exits the channel impacts the magnitude of cable tension. A spring tensioning and cam actuation mechanism were developed to account for changing cable circuit path lengths during wrist pitch. This work shows that pulley-free cable wrist mechanisms can facilitate miniaturization below current feasible sizes while retaining compact articulation at the expense of increases in friction under constant cable velocity conditions.

Energy-minimizing kinematics in hovering insect flight

2007 ◽  
Vol 582 ◽  
pp. 153-168 ◽  
Author(s):  
GORDON J. BERMAN ◽  
Z. JANE WANG
Keyword(s):  
Degrees Of Freedom ◽  
Insect Flight ◽  
Bombus Terrestris ◽  
Leading Edge ◽  
Sensitivity Analyses ◽  
Aerodynamic Forces ◽  
Insect Wing ◽  
Gradient Based ◽  
Constant Altitude ◽  
Free Falling

We investigate aspects of hovering insect flight by finding the optimal wing kinematics which minimize power consumption while still providing enough lift to maintain a time-averaged constant altitude over one flapping period. In particular, we study the flight of three insects whose masses vary by approximately three orders of magnitude: fruitfly (Drosophila melanogaster), bumblebee (Bombus terrestris), and hawkmoth (Manduca sexta). Here, we model an insect wing as a rigid body with three rotational degrees of freedom. The aerodynamic forces are modelled via a quasi-steady model of a thin plate interacting with the surrounding fluid. The advantage of this model, as opposed to the more computationally costly method of direct numerical simulation via computational fluid dynamics, is that it allows us to perform optimization procedures and detailed sensitivity analyses which require many cost function evaluations. The optimal solutions are found via a hybrid optimization algorithm combining aspects of a genetic algorithm and a gradient-based optimizer. We find that the results of this optimization yield kinematics which are qualitatively and quantitatively similar to previously observed data. We also perform sensitivity analyses on parameters of the optimal kinematics to gain insight into the values of the observed optima. Additionally, we find that all of the optimal kinematics found here maintain the same leading edge throughout the stroke, as is the case for nearly all insect wing motions. We show that this type of stroke takes advantage of a passive wing rotation in which aerodynamic forces help to reverse the wing pitch, similar to the turning of a free-falling leaf.

A Slice Finite Element Model for Bending Analysis of Curved Beams

2011 ◽  
Vol 338 ◽  
pp. 282-285 ◽  
Author(s):  
Wen Guang Jiang ◽  
Li Juan Yan
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Finite Element Modelling ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Curved Beams ◽  
Pure Bending ◽  
Cross Sectional ◽  
Bending Analysis ◽  
Constraint Equations

The pure bending analysis of curved beams may be performed by finite element modelling of only a representative slice sector of the beam cross-section, by establishing exact deformation relationships between degrees of freedom of corresponding nodes on the corresponding artificial cross-sectional boundaries. These deformation relationships can be conveniently realized using constraint equations between nodal degrees of freedom. Numerical example has been given to demonstrate the accuracy and effectiveness of the proposed method.

scholarly journals The chaotic set and the cross section for chaotic scattering in three degrees of freedom

2010 ◽  
Vol 12 (10) ◽  
pp. 103021 ◽  
Author(s):  
C Jung ◽  
O Merlo ◽  
T H Seligman ◽  
W P K Zapfe
Keyword(s):  
Cross Section ◽  
Degrees Of Freedom ◽  
Chaotic Scattering ◽  
The Cross ◽  
Three Degrees Of Freedom

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

A tilting high temperature gas reaction chamber for the JEM 7A T.E.M.

1978 ◽  
Vol 36 (1) ◽  
pp. 70-71
Author(s):  
Brian L. Rhoades
Keyword(s):  
Cross Section ◽  
Reaction Chamber ◽  
Objective Lens ◽  
Reduced Cross Section ◽  
Cross Sectional ◽  
Structural Investigations ◽  
Transmission Electron ◽  
Dynamic Experiments ◽  
Successful Design ◽  
Thermocouple Junction

A gas reaction chamber has been designed and constructed for the JEM 7A transmission electron microscope which is based on a notably successful design by Hashimoto et. al. but which provides specimen tilting facilities of ± 15° aboutany axis in the plane of the specimen.It has been difficult to provide tilting facilities on environmental chambers for 100 kV microscopes owing to the fundamental lack of available space within the objective lens and the scope of structural investigations possible during dynamic experiments has been limited with previous specimen chambers not possessing this facility.A cross sectional diagram of the specimen chamber is shown in figure 1. The specimen is placed on a platinum ribbon which is mounted on a mica ring of the type shown in figure 2. The ribbon is heated by direct current, and a thermocouple junction spot welded to the section of the ribbon of reduced cross section enables temperature measurement at the point where localised heating occurs.

Microstructure of laser-irradiated, conducting Kapton polyimide

1995 ◽  
Vol 53 ◽  
pp. 502-503
Author(s):  
D. L. Callahan ◽  
Z. Ball ◽  
H. M. Phillips ◽  
R. Sauerbrey
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Film Surface ◽  
Cross Sectional ◽  
General Utility ◽  
Transmission Electron ◽  
Considerable Debate ◽  
Potential Applications

Ultraviolet laser-irradiation can be used to induce an insulator-to-conductor phase transition on the surface of Kapton polyimide. Such structures have potential applications as resistors or conductors for VLSI applications as well as general utility electrodes. Although the percolative nature of the phase transformation has been well-established, there has been little definitive work on the mechanism or extent of transformation. In particular, there has been considerable debate about whether or not the transition is primarily photothermal in nature, as we propose, or photochemical. In this study, cross-sectional optical microscopy and transmission electron microscopy are utilized to characterize the nature of microstructural changes associated with the laser-induced pyrolysis of polyimide.Laser-modified polyimide samples initially 12 μm thick were prepared in cross-section by standard ultramicrotomy. Resulting contraction in parallel to the film surface has led to distortions in apparent magnification. The scale bars shown are calibrated for the direction normal to the film surface only.

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