IUTAM 2019
Phase Transformations in Shape Memory Materials: Modeling and Applications
The University of Texas at Austin
April 28 – May 2, 2019
Summary
This symposium aims to bring together researchers who, through the use of experiment, theory and numerical modeling, try to understand the complex nonlinear phenomena that govern SMA materials and structural behavior. This includes mechanicians, materials scientists, applied physicists, and numerical modelers. We expect this diversity of backgrounds to result in cross-fertilization of ideas and approaches that will lead to significant advances to the field. Each of the three co-chairs brings experience in SMA and smart materials and structures mechanical behavior and modeling. This experience guarantees that the symposium synthesis will be wide, strong, diverse, and ultimately successful. The symposium will be held at the University of Texas at Austin, which has the conference facilities and resident expertise that will ensure the organizational success of this symposium.
Shape memory alloys (SMAs) exhibit the unique characteristics of: (a) shape memory, where the material reverts back to its original shape shape after undergoing seemingly permanent deformation by a modest change in temperature; and (b) pseudoelasticity that describes the ability of the material to be deformed to strains of a few percent and return to its unstrained configuration on unloading. Both effects are derived from diffusionless transformations between two solid-state phases, austenite and martensite, which can be induced by either changes in temperature or stress. These characteristics are being exploited in novel structural applications in diverse fields like biomedical devices, aerospace components, damping and energy absorption, MEMS, morphing of structures, and generally “smart” structures.
The constitutive modeling of the complex behavior of SMAs is an essential requirement in the design of such SMA structures. Despite significant advances in the development of such models, the field remains a challenge because of complications such as inhomogeneous deformations that can take place, complex thermomechanical interactions, and by significant tension/compression asymmetries caused by processing-induced crystallographic texture. In particular these nonlinearities have been shown to interact with structural instabilities that can lead to failure. Modeling of such instabilities is very sensitive to the details of the material constitutive behavior.
SMA constitutive modeling has tapped into a wide range of tools including phenomenological macroscopic models forpolycrystals, single crystal models that identify individual transformation systems, phase-field models that resolveindividual austenite/martensite boundaries, and micromechanical modeling approaches that attempt to bridge scales.Recent experimental studies have focused on characterizing SMA material responses under a wide range of multiaxial mechanical stress states and temperature histories for both pseudoelastic and shape memory behavior.
Program and Abstracts
Group Photo
