By hybridizing or incorporating shape-memory materials with other functional materials or structural materials, smart composites can be fabricated which may utilize the unique functions or properties of the individual bulk materials to achieve multiple responses and optimal properties, or, to tune their properties to adapt to environmental changes. A variety of shape-memory hybrid composites have been designed and manufactured, with shape-memory elements being either the matrix or the reinforcement. The hybrid composites provide tremendous potential for creating new paradigms for material–structural interactions and demonstrate varying success in many engineering applications. This review, from the standpoint of materials science, will give a state-of-the-art survey on the various shape-memory hybrid smart composites developed during the last decade. Emphasis is placed on the design, fabrication, characterization and performance of fibre-reinforced, particle-reinforced and multi-layered thin-film shape-memory composites.

Shape memory materials and hybrid composites for smart systems. Part II shape-memory hybrid composites

A review of constitutive models and modeling techniques for shape memory alloys

General information Publication status: Published Organisations: Department of Energy Conversion and Storage, Electrofunctional materials, Department of Wind Energy, Composites Mechanics and Materials Mechanics, University of Barcelona Contributors: Tusek, J., Engelbrecht, K., Millán-Solsona, R., Mañosa, L., Vives, E., Mikkelsen, L. P., Pryds, N. Number of pages: 5 Publication date: 2015 Peer-reviewed: Yes

The Elastocaloric Effect: A Way to Cool Efficiently

Shape memory alloy actuators in smart structures: Modeling and simulation

A new macro-scale model of shape memory alloys is developed within the framework of generalized standard materials with internal constraints [Moumni, Z, 1995 Sur la modelisation du changement de phase a l’etat solide PhD Thesis, Ecole Nationale Superieure des Ponts et Chaussees] It is shown that the introduction of two state variables: the martensite volume fraction and the martensite orientation strain tensor, is sufficient to account for several effects exhibited by SMAs subject to thermomechanical loading, namely: self-accommodation, orientation and reorientation or martensite, as well as superelasticity and one-way shape memory These phenomena are simulated using the same set of constitutive equations and evolution laws A simple procedure for identifying the parameters of the model is described in detail and a validation against experimental data is conducted The model is then used to analyze a 3D SMA structure representing a superelastic stent Cyclic loading and other pertaining phenomena like training and two-way shape memory are considered in the second part of this paper

A three-dimensional model of the thermomechanical behavior of shape memory alloys

Here we will present a simplification of the form of one popular shape memory alloy (SMA) constitutive model. This simplification allows a more compact written form and hence easier calculations with the one-dimensional SMA constitutive law first developed by Tanaka, later modified by Liang and Rogers, and again by Brinson. In addition, a new derivation of the model will be given based on micromechanics. In this context, comparisons between the Tanaka and two other models will be presented and implications discussed. It will be shown that the constitutive models are in fact quite similar, and that the important distinction between these SMA models is primarily in the formulation of the transformation kinetics. Several examples will be presented utilizing the models.

Simplifications and Comparisons of Shape Memory Alloy Constitutive Models

In this paper the active control of beam deflection through heating and cooling of Shape Memory Alloy (SMA) wires is examined. A phenomenological constitutive law for SMA wires is coupled with beam theory to provide predictions of beam shape upon temperature change in the SMA actuator. Both the linear and nonlinear beam theory are presented, enabling calculation of large deflections. Examples for a single wire attached at the tip of a uniform beam are given, but the procedure can easily be generalized for other configurations and utilized in control algorithms. Issues of design constraints for shape control with shape memory wires are addressed and the model is qualitatively verified by experiments.

M. S. Huang

Papers

Simplifications and Comparisons of Shape Memory Alloy Constitutive Models

Analysis of Controlled Beam Deflections Using SMA Wires