experimental and numerical study to design knitted

EXPERIMENTAL AND NUMERICAL STUDY TO DESIGN
KNITTED NICKEL-TITANE SUPERELASTIC TEXTILES
USED IN THE FIELD OF FLEXIBLE ORTHOSES
INSTITUTIONS
Grenoble
Institute of
Technology
CNRS
Université
Grenoble Alpes
University of
Savoie
Durée: 3 years
Profil recherché : Master degree in mechanics and/or materials
sciences
Required skills: Mechanics, material behavior, numerical FE
simulations, experimentation, English.
CONTACT
Living in
GRENOBLE
Contacts :
N.Connesson ([email protected]) and D. Favier (
[email protected])
Laboratoire TIMC-IMAG, Université Grenoble Alpes.
Codirection Ludek Heller, Académie des Sciences, Prague
The PhD work will focus on superelastic Nickel-Titane textiles. NiTi
shape memory alloys present different mechanical singular
particularities as super-elasticity (pseudo-elasticity up to 10%) and
shape setting (a NiTi wire set in a specific shape and heated will
keep this shape as reference position after cooling).
NiTi knitted textiles present an anisotropic behavior at the end of
the manufacturing process (Fig.1 c, blue). If a specific shape setting
is applied to NiTi textile, its mechanical behavior is strongly
modified (Fig.1 c, red).
The aim of this PhD is to continue the experimental and numerical
work initiated in a first PhD to predict the NiTi textiles mechanical
behavior depending on different parameters (applied shape setting
(knit geometry), NiTi alloy composition and heat treatments) and on
the loading configuration (equi-biaxial, biaxial, etc). The idea is to
be eventually able to propose specific design so as to obtain a
targeted mechanical behavior defined during a companion CIFRE
PhD that will simultaneously start at the society Demeure
Orthopedie to define new flexible orthoses.
In a first step, the PhD student will learn the different experimental
and simulations technics developed during the previous PhD (Fig2
and 3). The student will then analyze experimentally and
numerically the impact of different shape setting on the mechanical
behavior of NiTi textile. These results will be used in the design of
new
flexible
orthoses.
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Figure 1- a) b), c) Knitted NiTi with different initial shape setting; c) mechanical behavior
and anisotropy depending on the initial shape shown in a) and b). Superelastic at room
temperature, diameter of 0.1mm [Heller2011].
Figure 2- Inner structure geometry in a FE software using symmetry boundary
conditions.
Figure 3- Left: setup picture. Right: experimental setup principle. [Tissot2016]
[Heller2011] Heller, L. and Marvalová, B. and Vlach, J. and Janouchová, K. and
Syrovátková, M. and Hanuš, J. (2011) Damping Capacity of Superelastic Nickel-Titanium
Plain Textiles. Springer Proc. in Phy. 565-572, doi:10.1007/978-94-007-2069-5_76
[Tissot2016] F. Tissot , N. Connesson, L. Heller, Y. Payan, D. Favier, Experimental Setup
To Perform Uniform Plane Biaxial Tests On Soft Membranes Including Measurement Of
Boundary Load Distribution, (submitted), Experimental Mechanics
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Centre of Excellence of Multifunctional Architectured Materials
Direction de la Recherche - 46 avenue Félix Viallet 38031 Grenoble Cedex 01 - FRANCE
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