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Proceedings Paper

Comparison between generation of recovery stresses in shape memory wires and composites: theory and reality
Author(s): Jan Schrooten; Kelly A. Tsoi; Rudy Stalmans; Yanjun Zheng; Petr Sittner
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Paper Abstract

An important property of shape memory (SMA) wires is the generation of high stresses when the strain recovery is impeded during heating. These stresses are called recovery stresses and can reach stress levels up to 800 MPa. In a first step this paper compares and discusses the recovery stress generation and mechanism in different SMA-wires based on experimental results. All experiments were performed on a specially equipped thermomechanical testing apparatus. Complex stress-, strain-, and temperature profiles can be programmed to study the thermomechanical behavior of a SMA. The knowledge of these recovery stresses was applied for composite materials. Embedding pre-strained SMA-wires in a composite result in a material with adaptive properties that are related to the reversible martensitic transformation in the SMA-wires. The behavior of the SMA-composites was studied in three ways. Starting from the experimental results on SMA-wires and the knowledge of composite materials, the behavior of the SMA- composites was predicted. A computer simulation model has been used for the same purpose. Thirdly, thermomechanical experiments were performed on the SMA-composites. The theoretically calculated and the simulated results were validated by comparison with these experimental results. In conclusion, links were established between the recovery stress behavior of a SMA-wire and the thermomechanical behavior of SMA-composites. This knowledge can be used to accurately design SMA-composites based on material data of individual SMA-wires.

Paper Details

Date Published: 6 April 2001
PDF: 11 pages
Proc. SPIE 4234, Smart Materials, (6 April 2001); doi: 10.1117/12.424397
Show Author Affiliations
Jan Schrooten, Katholieke Univ. Leuven (Belgium)
Kelly A. Tsoi, Katholieke Univ. Leuven (Australia)
Rudy Stalmans, Katholieke Univ. Leuven (Belgium)
Yanjun Zheng, Katholieke Univ. Leuven (Belgium)
Petr Sittner, Institute of Physics (Czech Republic)

Published in SPIE Proceedings Vol. 4234:
Smart Materials
Alan R. Wilson; Hiroshi Asanuma, Editor(s)

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