Evaluation of bending rigidity and torsional rigidity of double-cylinder structure with open-section members for morphing structure

2020 ◽  
Vol 2020 (0) ◽  
pp. 16D10
Author(s):  
Yusuke ARAI ◽  
Hiroaki TANAKA
Keyword(s):  
Torsional Rigidity ◽  
Bending Rigidity ◽  
Open Section ◽  
Morphing Structure

scholarly journals Verification of the effect of yarn torsional rigidity on fabric bending rigidity in any direction

2016 ◽  
Vol 87 (4) ◽  
pp. 424-432 ◽  
Author(s):  
Julie Peiffer ◽  
KyoungOk Kim ◽  
Masayuki Takatera
Keyword(s):  
Torsional Rigidity ◽  
Cotton Fabrics ◽  
Bending Rigidity ◽  
Pure Bending ◽  
Experimental Values

The effect of yarn torsional rigidity was verified on the Cooper model for fabric bending rigidity in any direction. We made five cotton fabrics with different weft densities and prepared three commercial fabrics as experimental samples. The torsional rigidity of yarn from the bobbin and that of yarn directly extracted from fabric were measured with a yarn torsional tester. The bending rigidity of yarn from the bobbin was measured using the same pure bending tester as used in fabric bending testing. The bending rigidity of thin fabric was calculated using torsional rigidities of yarns extracted from the fabric and showed better agreement with the experimental values than that calculated using the torsional rigidity of yarn from the bobbin. Indeed, measurements showed that the torsional rigidity of yarn from the bobbin was appreciably higher than the torsional rigidity of yarn from the fabric. This is due to the crimp in the yarn. The fabric bending rigidity can be predicted using the Cooper model with torsional rigidities of yarns extracted from the fabric.

Elastic Torsion in the Presence of Initial Axial Stress

1950 ◽  
Vol 17 (4) ◽  
pp. 383-387
Author(s):  
J. N. Goodier
Keyword(s):  
Cross Section ◽  
Axial Stress ◽  
Torsional Rigidity ◽  
Torsional Stiffness ◽  
Lateral Buckling ◽  
Initial Tension ◽  
Open Section ◽  
Thin Walled ◽  
The Cross

Abstract The torsional rigidity, for small elastic torsion, of bars of thin-walled open section, is, in general, altered by initial tension, compression, bending, or other axial stress. This appears in the increase of torsional stiffness of strips due to tension, in the decrease to zero in open sections which buckle torsionally as columns, and also has an influence on lateral buckling of beams. This paper contains an extension of the Saint Venant solution for ordinary torsion to the problem of torsion in the presence of initial axial stress with any distribution on the cross section. The results are confirmed by tests, and validate the intuitively derived formulas which are in use.

Characteristics Analysis and Optimization of Flying-Wing Vehicle Structure

2014 ◽  
Vol 1077 ◽  
pp. 177-184 ◽  
Author(s):  
Hong Xia Zhou ◽  
Bin Liu
Keyword(s):  
Dynamic Model ◽  
Axial Force ◽  
Structural Characteristics ◽  
Torsional Rigidity ◽  
Bending Rigidity ◽  
Static Test ◽  
Wing Span ◽  
Resonance Test ◽  
Vehicle Structure ◽  
Characteristics Analysis

To study structural characteristics of flying-wing vehicle, static and dynamic model of half wing span, static and dynamic model of all wing span, optimization model were established. Based on associated static test and ground resonance test data, these models were modified to implement static, dynamic and optimization analysis. Results demonstrated that structural bending and torsional deformations are mainly at outer wing surface. Torsion at inner wing is positive, while torsion at outer wing is negative. Total spar axial force along the wing span increases gradually from inner wing to outer wing and then decreases gradually after reaching the inner-outer wing interface. After axial force is transmitted to the inner wing, it is going to concentrate at the rear spar obviously. Structural bending rigidity and torsional rigidity satisfy requirements of both static force and flutter, without flutter problem of main structural mode. Viewed from the optimization size, ±45° and 0° skin at inner-outer wing turn thickens significantly. This can increase structural bending and torsional rigidity, which is good for satisfying multiple constraints comprehensively.

Vibration Propagation in Ordered and Disordered Orthotropic Single-Leaf Rib-Stiffened Panels

2011 ◽  
Vol 317-319 ◽  
pp. 287-291 ◽  
Author(s):  
Da Ye Yu ◽  
Gui Lan Yu
Keyword(s):  
Periodic Structures ◽  
Plate Theory ◽  
Torsional Rigidity ◽  
Span Length ◽  
Bending Rigidity ◽  
Stiffened Panels ◽  
Vibration Localization ◽  
Single Leaf ◽  
Thin Plate Theory ◽  
Relative Bending Rigidity

Abstract Based on the thin plate theory and the transfer matrix method, the vibration propagation in periodical orthotropic single-leaf rib-stiffened panels is studied. The localization factors of the ordered and disordered periodic systems are calculated. The numerical results show that the anisotropy of the plate affects the propagation of vibration in the pannels. With the relative bending rigidity increasing, or with the relative torsional rigidity increasing, the width of stopbands increases in low dimenionless frequencies. The vibration localization phenomenon occurs in the span-length disordered periodic structures and it is enhanced with the increasing disorder of span-length.

scholarly journals Innovative Blade Trailing Edge Flap Design Concept using Flexible Torsion Bar and Worm Drive

2020 ◽  
Vol 1 (3) ◽  
pp. 101-106
Author(s):  
Kwangtae Ha
Keyword(s):  
Torsional Rigidity ◽  
Turbine Rotor ◽  
Worm Gear ◽  
Bending Rigidity ◽  
Trailing Edge ◽  
Turbine Rotor Blade ◽  
Gear Drive ◽  
Actuation System ◽  
Trailing Edge Flap ◽  
Torsion Bar

In this paper, a simple but effective trailing edge flap system was proposed. This preliminary concept uses a more practical and stable actuation system which consists of a motor-driven worm gear drive and flexible torsion bar. The flexible torsion bar is designed to be easily twisted while keeping bending rigidity as a sup-port and the worm gear drive not only provides a high torque to overcome aero-dynamic forces on the flap area and the torsional rigidity of the support bar, but also acts as a brake to avoid instability due to the high torsional flexibility of sup-port bar. A preliminary level design study was performed to show the applicability of the new trailing edge flap system for wind turbine rotor blade or helicopter blade.

scholarly journals A Design of an Unmanned Electric Tractor Platform

Agriculture ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 112
Author(s):  
Yung-Chuan Chen ◽  
Li-Wen Chen ◽  
Ming-Yen Chang
Keyword(s):  
Lithium Batteries ◽  
Induction Motors ◽  
Smallholder Farmers ◽  
Torsional Rigidity ◽  
Future Trend ◽  
Ecological Environment ◽  
Body Structure ◽  
Bending Rigidity ◽  
Agricultural Machinery ◽  
Toxic Gases

The tractor is a vehicle often used in agriculture. It is mainly used to tow other unpowered agricultural machinery for farming, harvesting, and seeding. They consume a lot of fuel with emissions that often contain a large amount of toxic gases, which seriously jeopardize human health and the ecological environment. Therefore, the electrical tractor is bound to become a future trend. The objective of this study is to design and implement a lightweight, energy-saving, and less polluting electric tractor, which meets the requirements of existing smallholder farmers, equipped with unmanned technology and multi-functions to assist labor and to provide the potential for unmanned operation. We reduced the weight of the tractor body structure to 101 kg, and the bending rigidity and torsional rigidity reached 11,579 N/mm and 4923 Nm/deg, respectively. Two 7.5 kW induction motors driven by lithium batteries were applied, which allows at least 3.5 h of working time.

The Development of a Split-Tube Flexure

2000 ◽  
Author(s):  
Michael Goldfarb ◽  
John E. Speich
Keyword(s):  
Range Of Motion ◽  
Robot Manipulators ◽  
Bending Rigidity ◽  
Revolute Joint ◽  
Open Section ◽  
Joint Characteristics ◽  
Beam Type ◽  
Thin Walled

Abstract This paper describes the design of a flexure joint, called the split-tube flexure, which can provide a considerably larger range of motion and significantly better multi-axis revolute joint characteristics than a conventional beam-type flexure. Specifically, the flexure joint contrasts the torsional compliance of a thin-walled open-section member with its bending rigidity to produce kinematically well-behaved revolute motion. The joint proves particularly useful in applications requiring kinematically well-behaved large motions, such as in robot manipulators.

Numerical Simulation of the Mechanical Behaviour of Single-Walled Carbon Nanotube Heterojunctions

2016 ◽  
Vol 38 ◽  
pp. 73-87 ◽  
Author(s):  
Nataliya A. Sakharova ◽  
André F.G. Pereira ◽  
Jorge M. Antunes ◽  
José Valdemar Fernandes
Keyword(s):  
Carbon Nanotube ◽  
Mechanical Behaviour ◽  
Torsional Rigidity ◽  
Three Dimensional ◽  
Element Model ◽  
Elastic Behaviour ◽  
Bending Rigidity ◽  
Single Walled Carbon Nanotube ◽  
Single Walled Carbon ◽  
Three Dimensional Finite Element

The study of the mechanical behaviour of single-walled carbon nanotube heterojunctions has been carried out, implementing nanoscale continuum approach. A three-dimensional finite element model is used in order to evaluate the elastic behaviour of cone heterojunctions. It is shown that the bending rigidity of heterojunctions is sensitive to bending conditions. The torsional rigidity does not depend on torsion conditions. Both rigidities of the heterojunction are compared with those of the thinner and thicker constituent nanotubes.

scholarly journals Buckling of a soap film spanning a flexible loop resistant to bending and twisting

2014 ◽  
Vol 470 (2172) ◽  
pp. 20140368 ◽  
Author(s):  
Aisa Biria ◽  
Eliot Fried
Keyword(s):  
Torsional Rigidity ◽  
Soap Film ◽  
Plateau Problem ◽  
Bending Rigidity ◽  
Energy Contribution ◽  
Lagrange Equations ◽  
Buckling Modes ◽  
Flexible Loop ◽  
A Value ◽  
The Stability

A generalization of the Euler–Plateau problem to account for the energy contribution due to twisting of the bounding loop is proposed. Euler–Lagrange equations are derived in a parametrized setting and a buckling analysis is performed. A pair of dimensionless parameters govern buckling from a flat, circular ground state. While one of these is familiar from the Euler–Plateau problem, the other encompasses information about the ratio of the torsional rigidity to the bending rigidity, the twist density and the size of the loop. For sufficiently small values of the latter parameter, two separate groups of buckling modes are identified. However, for values of that parameter exceeding the critical twist density arising in Michell's study of the stability of a twisted elastic ring, only one group of buckling modes exists. Buckling diagrams indicate that a loop with greater torsional rigidity shows more resistance to transverse buckling. Additionally, a twisted flexible loop spanned by a soap film buckles at a value of the twist density less that the value at which buckling would occur if the soap film were absent.

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