Desenvolvimento de um atuador torcional baseado em ligas com memória de forma NiTi aplicado em um dispositivo do tipo leme aeronáutico

Abstract

The maturity degree in the field of smart materials and structures is evidenced by the extensive research efforts aimed at the development of industrial products. Among the various options available, Shape Memory Alloys (SMAs) have received considerable attention due to their ease of use in motion actuators, microcontrollers, and sensors. These alloys exhibit two fundamental properties: Superelasticity (SE) and Shape Memory Effect (SME), which arise from an austenite/martensite phase transformation. Actuators made from these materials are relatively lightweight, easy to manufacture, and have the ability to generate high actuation forces through controlled application of heat. As a result, these materials can be employed in the design of various engineering systems, replacing hydraulic, pneumatic, and electric actuators, with the possibility of use at microscopic scales, coupled with design flexibility. In this context, the aim of the present study is dedicated to the fabrication and evaluation of the thermo-mechanical behavior of torsion helical springs made from NiTi-based Shape Memory Alloys, which exhibit the combined SE/SME effect when activated. The effectiveness of this concept is demonstrated by constructing a rudder prototype to verify its functional properties. Prior to this strategy, preliminary studies were conducted to characterize the NiTi SMA wires, followed by tests to extract information about the dynamics exhibited by NiTi SMA torsion springs. Notably, the design of a new system for measuring the force generated by each spring deserves attention. The results demonstrate the conditions under which the highest actuation capabilities can be achieved, specifically by increasing the wire diameter and number of turns, associated with large angular displacements. Different curvature configurations of the rudder were obtained by reversing the direction of actuation. Consequently, maximum longitudinal displacements of 30° were recorded when the movement was executed towards the left and 40° in the opposite direction. There are still significant technological challenges to be overcome before the practical consolidation of NiTi SMA torsion springs; however, this proposal shows potential and should not be disregarded.