Shape Memory Alloys (SMA) are a group of metallic alloys that can return to their original shape when subjected temperature transformation between two phases. SMAs have been used as an alternative solution conventional actuators in different applications the robotics, biomedical, aerospace and automation domains because characteristics; being one leading solutions fields such soft robotics bio-...

This study comprises finite element simulations and experimental studies of the shape memory effect due to the presence of SMA (shape memory alloy) wires in composite materials. FEA was performed using ANSYS, where the prestrain was modelled by equivalent changes in the expansion coefficient of the SMA. Three case-studies were simulated and their predictions were compared with experimental data...

Abstract Metal forming of shape memory alloys (SMA) can be challenging since these are very often brittle due to their intermetallic character. However, formability is needed not only for realising the desired geometry but also tailoring microstructure and functional properties. To investigate whether encapsulation in a steel shell improve alloys, Co 49 Ni 21 Ga 30 49.5 Fe 14.5 Mn 4.0 26.0 6.0 ...

The single crystal Cu-Al-Ni alloys became generally commercialized. It can be observed that response time of any single crystal Cu-Al-Ni-based shape memory alloy (SMA) actuator is greater than the necessary when it is used for human prosthesis. Moreover, the electrical SMA actuator type with better performance than the thermal one is very problematic for this type of crystal due to its low elec...

Heusler type Ni-Mn-Ga ferromagnetic shape memory alloys can demonstrate excellent magnetic shape memory effect in single crystals. However, such effect in polycrystalline alloys is greatly weakened due to the random distribution of crystallographic orientation. Microstructure optimization and texture control are of great significance and challenge to improve the functional behaviors of polycrys...

This paper investigates the applicabilty of an innovative bracing, called Articulated Quadrilateral (AQ) bracing system, which uses shape memory alloys (SMAs), for retroffiting low-rise to high-rise vulnerable SMFRs against strong ground motions. The paper investigates brace fundamental engineering characteristics, design of the system and also configuration of the brace (the proportion of SMA ...

Shape memory alloys are smart materials. Due to their ability to change into a previously imprinted actual shape through the means of thermal activation, they are suitable as actuators for microsystems and, within certain limitations, macroscopic systems. To apply these smart materials to a wide range of industrial applications, a simple method of controlling the actuator effect is required. Th...

This paper presents a three-dimensional constitutive model for shape-memory alloys that generalizes the one-dimensional model presented earlier (Sadjadpour and Bhattacharya 2007 Smart Mater. Struct. 16 S51–62). These models build on recent micromechanical studies of the underlying microstructure of shape-memory alloys, and a key idea is that of an effective transformation strain of the martensi...

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 f...

are compared with the experimental results. In these test results the shape memory alloys behavior as: super elasticity under various temperatures, loading rate effects, asymmetry in tension and pressure, various loops of loading and unloading, hydrostatic pressure effects, different proportional tension-shear biaxial loading and unloading, and also deviation from normality due to non-proportio...