Three-dimensional penrose tiling under phason strain field I

1989 ◽  
Vol 71 (1) ◽  
pp. 1-4 ◽  
Author(s):  
J.R. Sun ◽  
X.S. Chen
Keyword(s):  
Strain Field ◽  
Three Dimensional ◽  
Penrose Tiling

scholarly journals A new methodology to identify minimum strain anatomical lines based on 3-D digital image correlation

2017 ◽  
Vol 8 (2) ◽  
pp. 337-347 ◽  
Author(s):  
Jorge Barrios-Muriel ◽  
Francisco Javier Alonso Sánchez ◽  
David Rodríguez Salgado ◽  
Francisco Romero-Sánchez
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Field ◽  
Three Dimensional ◽  
Wearable Devices ◽  
Plane Motion ◽  
Human Motion ◽  
The Body ◽  
Image Correlation ◽  
Minimum Deformation

Abstract. Today there is continuous development of wearable devices in various fields such as sportswear, orthotics and personal gadgets, among others. The design of these devices involves the human body as a support environment. Based on this premise, the development of wearable devices requires an improved understanding of the skin strain field of the body segment during human motion. This paper presents a methodology based on a three dimensional digital image correlation (3D-DIC) system to measure the skin strain field and to estimate anatomical lines with minimum deformation as design criteria for the aforementioned wearable devices. The errors of displacement and strain measurement related to 3-D reconstruction and out-of-plane motion are investigated and the results are acceptable in the case of large deformation. This approach can be an effective tool to improve the design of wearable devices in the clinical orthopaedics and ergonomics fields, where comfort plays a key role in supporting the rehabilitation process.

Three-dimensional instability of Burgers and Lamb–Oseen vortices in a strain field

1999 ◽  
Vol 378 ◽  
pp. 145-166 ◽  
Author(s):  
CHRISTOPHE ELOY ◽  
STÉPHANE LE DIZÈS
Keyword(s):  
Strain Field ◽  
Three Dimensional ◽  
Small Strain ◽  
Kelvin Waves ◽  
Large Reynolds Number ◽  
Axisymmetric Vortex ◽  
Burgers Vortex ◽  
Additional Strain ◽  
Instability Characteristic ◽  
Dimensional Instability

The linear stability of Burgers and Lamb–Oseen vortices is addressed when the vortex of circulation Γ and radius δ is subjected to an additional strain field of rate s perpendicular to the vorticity axis. The resulting non-axisymmetric vortex is analysed in the limit of large Reynolds number RΓ=Γ/v and small strain s[Lt ]Γ/δ2 by considering the approximations obtained by Moffatt et al. (1994) and Jiménez et al. (1996) for each case respectively. For both vortices, the TWMS instability (Tsai & Widnall 1976; Moore & Saffman 1975) is shown to be active, i.e. stationary helical Kelvin waves of azimuthal wavenumbers m=1 and m=−1 resonate and are amplified by the external strain in the neighbourhood of critical axial wavenumbers which are computed. The additional effects of diffusion for the Lamb–Oseen vortex and stretching for the Burgers vortex are proved to limit in time the resonance. The transient growth of the helical waves is analysed in detail for the distinguished scaling s∼Γ/ (δ2R1/2Γ). An amplitude equation describing the resonance is obtained and the maximum gain of the wave amplitudes is calculated. The effect of the vorticity profile on the instability characteristic as well as of a time-varying stretching rate are analysed. In particular the stretching rate maximizing the instability is calculated. The results are also discussed in the light of recent observations in experiments and numerical simulations. It is argued that the Kelvin waves resonance mechanism could explain various dynamical behaviours of vortex filaments in turbulence.

X-ray microbeam three-dimensional topography for dislocation strain-field analysis of 4H-SiC

2013 ◽  
Vol 114 (2) ◽  
pp. 023511 ◽  
Author(s):  
R. Tanuma ◽  
D. Mori ◽  
I. Kamata ◽  
H. Tsuchida
Keyword(s):  
Strain Field ◽  
Three Dimensional ◽  
Field Analysis ◽  
X Ray

Polycarbonate as a Model Material for Three-Dimensional Photoplasticity

1973 ◽  
Vol 40 (2) ◽  
pp. 600-605 ◽  
Author(s):  
J. W. Dally ◽  
A. Mulc
Keyword(s):  
Yield Point ◽  
Strain Field ◽  
Permanent Deformation ◽  
Three Dimensional ◽  
Model Material ◽  
Yield Behavior ◽  
Molecular Scale

Polycarbonate is a polymer which exhibits extreme toughness, a pronounced yield behavior, and the ability to flow extensively prior to fracture. These characteristics coupled with its birefringent properties indicate its suitability as a model material for photoelastic analyses. This study treats the photoplastic response of polycarbonate which has been deformed well beyond the yield point and unloaded. The strain field associated with this permanent deformation is related to the birefringence by the conventional strain-optic law. The birefringence is permanently locked in the polycarbonate models on a molecular scale. The model can be sliced to isolate planes of interest and the method can be applied to study permanent strains in plastically deformed three-dimensional bodies.

Study of ECAE Process by Using FEM

2006 ◽  
Vol 526 ◽  
pp. 193-198 ◽  
Author(s):  
Rodrigo Luri ◽  
C.J. Luis-Pérez
Keyword(s):  
Cross Section ◽  
Strain Field ◽  
Equal Channel Angular Extrusion ◽  
Three Dimensional ◽  
Extrusion Process ◽  
The Finite Element Method ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Circular Section ◽  
Processed Material

In this work, the strain field attained by using a severe plastic deformation (SPD) process called equal channel angular extrusion (ECAE) is studied by the finite element method (FEM). The three-dimensional model with circular section includes shear friction between the part and the die, the material strain hardening behaviour and a rigid-deformable contact between the billet and the die. In the ECAE process the part is extruded through two channels with similar diameter that intersect at an angle. When the extrusion process has been performed, the processed material remains it cross section, so there is not any geometric limitation to achieve the desired plastic strain. There are different ways of processing the material by using the ECAE process; those ways of processing are called routes. In this work two passages of route C have been simulated. Using route C means that the billet has been rotated 180º between each passage. Deformations imparted to the processed material have been calculated and a comparison with experimental results has been carried out.

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