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Design and Application of Shape Memory Actuators

Matthias Mertmann 

Memory-Metalle GmbH, Am Kesselhaus 5, Weil am Rhein 79576, Germany


The use of shape memory alloys in actuators offers the opportunity to develop robust, simple and lightweight elements for application in a multitude of different industries. Over the years, the intermetallic compound Nickel-Titanium (NiTi or NiTinol) has gained acceptance as a standard alloy in even though NiTinol is not the perfect alloy for all kinds of applications and industries. The major disadvantages of the material open a wide field for improvements in both, the mechanical design with the existent alloys and the development of new, improved alloy systems:

  • the lack of higher transformation temperatures in the available alloys in order to open the field of automotive applications (Mf > 85°C),
  • the non-linearity in the electrical resistivity in order to improve the controllability of the actuator,
  • the wide hysteresis, which has a significant effect on both, the dynamics of the actuator and the controllability.

Hence, there is a constant strive in the field towards an improvement of the related properties. However, significant steps forward are already possible if the usage of existent materials is optimized for the projected application and if the system is desiged in a most efficient way.

This paper provides an overview about existent designs, applications and alloys for actuators, as well as new shape memory actuator systems with improved performance.


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Presentation: Invited at E-MRS Fall Meeting 2007, Symposium E, by Matthias Mertmann
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-04-16 15:53
Revised:   2009-06-07 00:44