CARVALHO, C. C.; http://lattes.cnpq.br/6722348160458734; CARVALHO, Carlos Costa de.
Résumé:
Rectangular cross section springs are generally used in applications with limited
space, especially where total height is constrained. This type of spring stores
more energy in a smaller space than circular wire springs of comparable
dimensions, despite the non-uniform stress distribution. Thus, combining the
higher energy storage capacity of this type of spring with the active and functional
characteristics of shape memory alloys (SMA) has enabled an enhancement of
this mechanical element's functionalities. The study of the behavior of this type of
spring is crucial for predicting its mechanical performance, enabling its use in
applications that demand compact designs and high energy storage capacity.In
the literature, studies on SMA springs made from wire or filament are quite
common, but there are few reports on SMA springs with rectangular sections.
This work focused on the experimental mechanical behavior of springs made
from shape memory alloys, which was made possible by the infrastructure of
LaMMEA/UFCG. Classical material springs were commercially acquired, while
prototypes were produced using the investment casting process. In this research,
the behavior of rectangular section springs manufactured through investment
casting was studied using two alloys: Ni-Ti and Ti-Ni-Cu. A castability study was
conducted using computational simulations, and based on the results, the optimal
runner system design for spring casting was selected. Finally, the springs
underwent heat treatment and were characterized through tensile tests, tension
and compression at constant temperatures, and DSC analysis.
