Experimental Study of Multiaxial Behavior of SMA Materials Under Complex Cyclic Loadings
Experimental Study of Multiaxial Behavior of SMA Materials Under Complex Cyclic Loadings
Tuesday, May 21, 2013
OREA Pryamida Hotel
Shape memory alloys are materials which are able to recover a large inelastic deformation (up to 8%) under thermomechanical loadings. This interesting property makes these alloys suitable for the development of original applications in various domains like biomedical, aerospace, etc.
The thermomechanical study of shape memory alloys has been developed since only a small twenty years. Uniaxial behavior of these alloys is very well known but their behavior under complex loadings (ie, cyclic multixial proportional or non proportional) have not been studied a lot. This fact is paradoxical because the control of this aspect is crucial to discuss the design and the reliability of mechanical systems using these alloys. As it is known, the nature of loading affects seriously their behavior. Consequently, it is important to focalize the research efforts on the study of multiaxial thermomechanical behavior of shape memory alloys. These efforts should concern the experimental aspects by realizing pertinent tests and also the development of models. Authors proposed some experimental data concerning the thermomechanical behavior of SMA under complex loadings. These results are interesting but they can be enriched by extending to cyclic aspects. The proposed study concerns the thermomechanical behavior of shape memory alloys under complex cyclic loadings experimentally. The efforts are concentrated on NiTi and CuAlBe shape memory polycrystals. Proportional and non-proportional cyclic tests are realized on tubular samples. All the tests are accompanied by the electric resistance measurements. This permits to determine the transformation kinetic during non proportional loadings. The obtained results permit the identification of material parameters necessary for behavior models. This experimental data base permits also the comparison between different modeling strategies.
The thermomechanical study of shape memory alloys has been developed since only a small twenty years. Uniaxial behavior of these alloys is very well known but their behavior under complex loadings (ie, cyclic multixial proportional or non proportional) have not been studied a lot. This fact is paradoxical because the control of this aspect is crucial to discuss the design and the reliability of mechanical systems using these alloys. As it is known, the nature of loading affects seriously their behavior. Consequently, it is important to focalize the research efforts on the study of multiaxial thermomechanical behavior of shape memory alloys. These efforts should concern the experimental aspects by realizing pertinent tests and also the development of models. Authors proposed some experimental data concerning the thermomechanical behavior of SMA under complex loadings. These results are interesting but they can be enriched by extending to cyclic aspects. The proposed study concerns the thermomechanical behavior of shape memory alloys under complex cyclic loadings experimentally. The efforts are concentrated on NiTi and CuAlBe shape memory polycrystals. Proportional and non-proportional cyclic tests are realized on tubular samples. All the tests are accompanied by the electric resistance measurements. This permits to determine the transformation kinetic during non proportional loadings. The obtained results permit the identification of material parameters necessary for behavior models. This experimental data base permits also the comparison between different modeling strategies.