Session: 04-09: SMA Enabled Smart Structures

Paper Number: 111227

111227 - Adaptive Aerodynamic Structure Based on Antagonistic Shape Memory Alloy Wire Actuators 

The thermal Sshape memory effect (SME) iss based on a phase transformation between abetween the high-temperature phase (austenite) and a low-temperature phase (martensite). With the STheME  a quasi-reversible plastic deformation can be made reversible by heat input, can bewhich is used to realize  SMA Aactuators [1, 2]. Depending on the application, heat this can be applied either in a either by process (thermostat)  or alternatively through ohmic heat created by an electric current flow through the shape memory alloy (SMA) material. Over the years, nickel titanium alloys (NiTi) have established themselves as most prominent SMA standard materials [3]. Because of their low space requirements due to variable shaping, a high energy density as well as low costs, SMA actuators, in particular SMA wires, are particularly well suited for the realization of compact and light-weight actuator systems. Due to availability and the dependence of the realizable frequency on the cooling rate, wire actuators are often used to increase the surface area and thus ensure a better temperature exchange.

In many technical applications, for example aerospace and automotive, but also in industry, aerodynamicvane geometries are the main components. The efficiency of such systems depends significantly on their shape o and the environmental conditions in various working scenariosf wings. Away from a rigid geometry, a system for shape and blade geometry adjustment can therefore adapt the geometry system to the existing environmental conditions and thus improve efficiency. From the point of view of climate change, an improvement in efficiency with the prospect of a high, absolute energy saving potential represents not only economic but also social benefits.

ThereforeTherefore, this work deals with the realization of a variable-angle blade geometry by antagonistic SMA wire actuators with a diameter of 500 μm. In addition to concept development, the focus is particularly on the design and construction and experimental validation of a first proof-of-concept demonstrator. On the electronic side, the demonstrator is supplemented by a control system based on a microcontroller. For interaction with the user, an angle sensor and an output display are also provided. Exemplary, one antagonistic pair of SMA wires is fully integrated into a 3D-printed blade structure. Initial tests show a rotation angle of 22° in one direction, totaling over 30° full range motion. One actuator system is designed to provide a calculated rotational moment of about 0,2 Nm. Forces can be scaled by integrating the same actuator system multiple times as it requires minimal construction space.

[1]    D. Reynaerts and H. Van Brussel, “Design aspects of shape memory actuators,” Mechatronics, vol. 8, no. 6, pp. 635–656, 1998, doi: 10.1016/S0957-4158(98)00023-3.

[2]    H. Janocha, Unkonventionelle Aktoren - Eine Einführung. München: Oldenburg Verlag, 2013.

[3]    J. Mohd Jani, M. Leary, A. Subic, and M. A. Gibson, “A review of shape memory alloy research, applications and opportunities,” Materials and Design, vol. 56. pp. 1078–1113, 2014, doi: 10.1016/j.matdes.2013.11.084.

Presenting Author: Paul Motzki Saarland University

Presenting Author Biography: Prof. Dr.-Ing. Paul Motzki is the director of the research division “smart material systems” at the Center for Mechatronics and Automation Technology (ZeMA gGmbH) in Saarbruecken, Germany. He received his B.Sc., M.Sc. and PhD degrees in Mechatronics and Systems Engineering from Saarland University, Germany. His research interests cover the design and development of multifunctional actuator-sensor-systems or artificial muscles based on smart materials like shape memory alloys and electroactive polymers. Special focus is on the emerging field of elastocalorics.