SIMÕES, J.B.; http://lattes.cnpq.br/8279861117114431; SIMÕES, Jackson de Brito.
Abstract:
In current stage of scientific and technological development in the area of
smart materiais, researches around the world have originated advances which are
able to allow their effective use as sensors and actuators, especially in case of
Shape Memory Alloys (SMA). This interest comes from the fact of these SMA being
metallic materiais able to recover high amount of residual strain (at about 5% in
uniaxial tensile) just by simple heating.
In this regard, this study had as main aim to manufacture and evaluate the bifunctional
thermomechanical behavior of SMA Belleville actuators (SMACON) from the
Ni-Ti alloy system. These elements manufactured with local technology are
appropriated for generation of forces in bolted connections through Shape Memory
Effect and Superelasticity. For this purpose, there were selected SMA compositions
of 55.3Ni-44,7Ti (wt%) and 14Nb-48Ni-38Ti (wt%) which have superelastic properties
at room temperature (~ 27 ° C). The method used to carry out the measurement of
generated force of SMACON versus time and temperature, involved deformation at
cryogenic temperatures, below - 50 ° C, and natural heating by the heat exchange
with local environment. The obtained results showed it is possible to use the
bifunctionality of the SMACON for static applications (bolted joint) and dynamic (energy
dissipation elements), keeping in mind that the generated forces were in the order of
2.5 kN and superelasticity of 40% in relation to height of the actuator.
