Design and application of shape memory actuators
- 625 Downloads
The use of shape memory alloys in actuators allows the development of robust, simple and lightweight elements for application in a multitude of different industries. Over the years, the intermetallic compound Nickel-Titanium (NiTi or Nitinol) together with its ternary and quaternary derivates has gained general acceptance as a standard alloy. Even though as many as 99% of all shape memory actuator applications make use of Nitinol there are certain properties of this alloy system which require further research in order to find improvements and new markets: • Lack of higher transformation temperatures in the available alloys in order to open the field of automotive applications (Mf temperature > 80 °C) • Non-linearity in the electrical resistivity in order to improve the controllability of the actuator, • Wide hysteresis in the temperature-vs.-strain behaviour, which has a signi-ficant effect on both, the dynamics of the actuator and its controllability. Hence, there is a constant strive in the field towards an improvement of the related properties. However, these improvements are not always just alloy composition related. There is also a tremendous potential in the thermomechanical treatment of the material and in the design of the actuator. Significant improvement steps are already possible if the usage of the existent materials is optimized for the projected application and if the actuator system is designed in the most efficient way. This paper provides an overview about existent designs, applications and alloys for use in actuators, as well as examples of new shape memory actuator application with improved performance. It also gives an overview about general design rules and reflects about the strengths of the material and the related opportunities for its application.
KeywordsShape Memory Shape Memory Alloy European Physical Journal Special Topic NiTi Shape Memory Alloy Shape Memory Material
Unable to display preview. Download preview PDF.
- A. Tuissi, P. Bassani, A. Mangioni et al., in Proceedings of the International Conference on Shape Memory and Superelastic Technology SMST 2004, edited by M. Mertmann (ASM International, Materials Park, OH, 2006), p. 501 Google Scholar
- F. Butera, in Shape Memory Alloys, Advances in Modelling and Applications, edited by F. Auricchio et al. (CIMNE, Barcelona, 2001), p. 405 Google Scholar
- M. Mertmann, in Proceedings of the 8th International Conference on New Actuators, edited by H. Borgmann (Actuator 2002, HVG Hanseatische Veranstaltungs-GmbH, Bremen, 2002), p. 85 Google Scholar
- M. Wagner, J. Frenzel, G. Eggeler, in Proceedings of the International Conference on Shape Memory and Superelastic Technology SMST 2004, edited by M. Mertmann (ASM International, Materials Park, OH, 2006), p. 103 Google Scholar
- P. Tautzenberger, H.-P. Kehrer, H. Nußkern, H.H. Kocher, Proceedings of the International Conference on Shape Memory and Superelastic Technology SMST 1993, edited by T.W. Duerig, (Monterey Institute of Advanced Studies, Monterey CA, 1993), p. 1295 Google Scholar
- M. Mertmann, in Proceedings of the 10th International Conference on New Actuators, edited by H. Borgmann (Actuator 2006, HVG Hanseatische Veranstaltungs-GmbH, Bremen, 2006), p. 461 Google Scholar