Actively controlled shape memory alloy actuators are useful for a variety of applications that require accurate shape control. For shape memory alloy wires, strain is modulated with temperature, usually by an applied voltage difference across the length. Numerical simulation using reinforcement learning has previously been used for determining the temperature strain relationship of a shape memo...

The two-way shape memory effect in a Ti36Ni49Hf15 high temperature shape memory alloy (SMA) has been systematically studied by bending tests. In the TiNiHf alloy, the martensite deformation is an effective method to get two-way shape memory effect even with a small deformation strain. When the TiNiHf alloy is deformed at a full martensite state, the deformation mechanism is the martensite orien...

A process for fabrication of shape memory alloy MEMS actuators on a elastomeric polymer substrate is described. These actuators are designed for use on innovative soft body robots. Patterned shape memory alloy (nitinol) is sputter deposited on a polyimide mesh structure. The mesh substrate acts as a bias spring to de-twin the shape memory alloy in the martensite phase. Significant portions of t...

As a new type of smart material, magnetic shape memory alloy has the advantages of a fast response frequency and outstanding strain capability in the field of microdrive and microposition actuators. The hysteresis nonlinearity in magnetic shape memory alloy actuators, however, limits system performance and further application. Here we propose a feedforward-feedback hybrid control method to impr...

-A nonlinear finite element procedure is developed which incorporates a thermodynami~ly derived cons~tutive law for shape. memory alloy material behavior. The constitutive equations include the necessary internal variables to account for the material transfo~ations and are utilized in a onedimensional finite element procedure that captures the unique shape memory alloy responses of pseudoelasti...

in the present research, in contrast to the available papers, not only the superelasticity but also the shape memory effects are taken into account in determination of the impact responses. at the same time, in addition to modifying brinson’s model for the shape memory alloys (smas), to include new parameters and loading events, and hertz contact law, distributions of the sma phases are conside...

the seismic performance of hybrid braces composed of steel and shape memory alloy (sma) was investigated in this paper. six types of hybrid braces were used, constituted by sma content of 0, 20, 40, 60, 80, and 100%. a nonlinear dynamic analysis was performed under el centro earthquake records, with the maximum acceleration of 0.6g and 0.9g. our results showed that the seismic performance, i.e....

the pseudo-elastic behavior of shape memory alloy (sma) truss and cantilever beam are investigated. brinson’s one-dimensional material model, which uses the twinned and detwinned martensite fractions separately as internal variables, is applied in the algorithm to establish the sma stress-strain characteristics. this material model also incorporates different young’s modulus for austenitic and ...

The ability to actively control the shape of aerospace structures has initiated research regarding the use of Shape Memory Alloy actuators. These actuators can be used for morphing or shape change by controlling their temperature, which is effectively done by applying a voltage difference across their length. The ability to characterize this temperature-strain relationship using Reinforcement L...