Page 14 - ASME SMASIS 2016 Program

Symposia

United Kingdom; and received the prestigious ETH Postdoctoral Fellow- which helps the industrial designer. The paper reports also a comparison
ship in 2012 from ETH Zurich, Switzerland. between the traditional ring spring and a superelastic ring spring on a
specific case study, giving a quantitative insight on the effectiveness of
His research focuses on integrating smart material systems with shape the proposed solution. The analytical model is verified by means of a finite
adaptable structures to generate engineering systems with novel function- element analysis of the ring spring with the inner ring in elastic material
alities. In particular, his research studies fundamental mechanisms for and the outer ring made of a superelastic material. The results of the FE
achieving inherent dynamic adaptation of commonly fixed mechanical analysis show a good agreement with the developed model both in terms
properties, such as geometry, stiffness, dynamic moduli and wave of force and dissipated energy. The main advantage of the proposed
propagation symmetry. To achieve this, structural nonlinear phenomena, solution is the increase in performance, even though the material cost of
such as buckling and multi-stability, are utilized to generate time-varying such a spring with bulk superelastic rings could limit the potential
mechanical properties. These ideas are applied to light-weight morphing applications. A possible workaround based on a different architecture with
wing structures, energy harvesting systems, time-varying metamaterials split rings and superelastic wires or strips is presented.
and programmable matter.

Dr. Arrieta was awarded Visiting Scholar position at ETH Zurich (2015), the
prestigious ETH Postdoctoral Fellowship (2012); Marie Curie Early Stage Biography
Researcher Fellowship (2010); Visiting Scholar position at the University of Andrea Spaggiari is a 33 years old mechatronics engineer. Andrea earned
Bristol (2010), and the ORS Ph.D. Scholarship Award (2007). He is a MS in 2006 (110/110 cum laude) at University of Modena and Reggio Emilia.
member of ASME and SPIE professional societies. In 2006 he earned a three-year PhD scholarship grant from MIUR “Youth
Plan”. In 2008 he won a local contest for young scientist with an innovative
biomedical device. In 2009 Andrea Spaggiari was chosen by the
Committee of the Region of the European Community for the Program

“100 young creative Talents of Europe” because of its patent about a
MODELLING AND SIMULATION OF SUPERELASTIC RING SPRINGS universal battery charger. He has got the PhD title at the School of “High
FOR HIGH ENERGY DISSIPATION Mechanics and Automotive Design & Technology”, in the course of
Modelling and Mechanical Design Methods in 2010. Andrea has an
ongoing collaboration with the University of Monterrey, Mexico about
Andrea Spaggiari magnetorheological fluid system design and previously he was hosted at
University of Modena and Reggio Emilia the Materials & Surface Science Institute at Limerick University, Ireland,
Modena MO, Italy working on multiscale modeling of void polymers. He established a
collaboration between the institutions which is still going on. From 2011
Andrea works as assistant professor at the University of Modena and
Reggio Emilia and he is the lecturer of the academic course of “New
Materials for Mechatronics Constructions” in the Master course of
Abstract
Mechatronic Engineering and “Integrated 3D Modelling for Mechatronic
The present work analyzes the behavior of the ring springs rings made of
design” in the course of Mechatronic Engineering. His current research
superelastic materials, typically Nickel Titanium alloys, but not limited to
interests are threefold. First he continues to develop the topic of his PhD,
this specific alloy. Classical ring springs are mechanical elements used in
studying the properties and the mechanical behaviour of structural
many industrial applications and in transport for shock absorption and
adhesives and their efficient modelling. Second he is working on
energy dissipation. They are constituted by a stack of internal and external
magneto-rheological fluids fundamental research and applications with an
metal rings (typically made of high strength steel), with tapered surfaces in
ongoing project in collaboration with a world leader company in automo-
contact with one another. Under the action of an axial load these surfaces
tive high performance brakes. Third, he works on shape memory alloys,
slide, the rings are deformed circumferentially and energy is dissipated
mainly for actuator design and development.
due to friction. Often lubricant is present between the rings to limit wear of
the rings, but in this analysis is not considered. The main advantages of
these springs are the high specific energy stored and the large damping
capacity due to sliding friction. Furthermore, the stiffness and damping are
independent on the strain rate and the temperature, which limits or avoids
the occurrence any resonance problems. The superelastic materials
considered is characterized by a stress plateau almost constant and large
reversible deformations. It can be used to replace traditional steels in ring
springs, which gives a significant performance. Compared to the tradition-

al steel version where energy is dissipated only due to friction, if almost
one of the inner or the outer rings is made of superelastic material there is
an increase of the dissipated energy thanks to the internal hysteresis of
the material. The work studies analytically, through simplified mechanical
14
models, the ring springs in traditional material and in superelastic material,
providing useful equations to dimension these mechanical elements,