Theoretical Analysis of Functionally Graded Shape Memory Alloy Beam Subjected to Pure Bending

This paper focuses on the size-dependent behaviors of functionally graded shape memory alloy (FG-SMA) microbeams based on the Bernoulli-Euler beam theory. It is taken into consideration that material properties, such as austenitic elastic modulus, martensitic elastic modulus and critical transformation stresses vary continuously along the longitudinal direction. According to the simplified linear shape memory alloy (SMA) constitutive equations and nonlocal strain gradient theory, the mechanical model was established via the principle of virtual work. Employing the Galerkin method, the governing differential equations were numerically solved. The functionally graded effect, nonlocal effect and size effect of the mechanical behaviors of the FG-SMA microbeam were numerically simulated and discussed. Results indicate that the mechanical behaviors of FG-SMA microbeams are distinctly size-dependent only when the ratio of material length scale parameter to the microbeam height is small enough. Both the increments of material nonlocal parameter and ratio of material length-scale parameter to the microbeam height all make the FG-SMA microbeam become softer. However, the stiffness increases with the increment of FG parameter. The FG parameter plays an important role in controlling the transverse deformation of the FG-SMA microbeam. This work can provide a theoretical basis for the design and application of FG-SMA microstructures.

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Wet Shape Memory Alloy Actuated Robotic Heart

ASME 2009 Dynamic Systems and Control Conference, Volume 2 ◽

10.1115/dscc2009-2755 ◽

2009 ◽

Cited By ~ 2

Author(s):

Joel Ertel ◽

Stephen Mascaro

Keyword(s):

Shape Memory Alloy ◽

Theoretical Analysis ◽

Shape Memory ◽

Preliminary Analysis ◽

Design Concept ◽

Design Parameters ◽

Sma Actuators ◽

Fluid Analysis ◽

Cold Fluid ◽

Simulation And Experiment

This paper presents a conceptual design and preliminary analysis for a biomimetic robotic heart. The purpose of the robotic heart is to distribute hot and cold fluid to robotic muscles composed of wet shape-memory alloy (SMA) actuators. The robotic heart is itself powered by wet SMA actuators. A heart design concept is proposed and the feasibility of self-sustaining motion is investigated through simulation and experiment. The chosen design employs symmetric pumping chambers for hot and cold fluid. Analysis of this design concept shows that there exists a range of design parameters that will allow the heart to output more fluid than it uses. Additionally, it is shown that the heartbeat rate decreases as the system increases in size, and that the number of actuators and their length limit the power output of the pump. Experimental results from a prototype heart agree with the predicted trends from theoretical analysis and simulation.

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In Situ Structural Characterization of Functionally Graded Ni–Ti Shape Memory Alloy During Tensile Loading

Shape Memory and Superelasticity ◽

10.1007/s40830-019-00237-2 ◽

2019 ◽

Vol 5 (4) ◽

pp. 457-467 ◽

Cited By ~ 3

Author(s):

Francisco M. Braz Fernandes ◽

Edgar Camacho ◽

Patrícia F. Rodrigues ◽

Patrick Inácio ◽

Telmo G. Santos ◽

...

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Structural Characterization ◽

Tensile Loading ◽

Functionally Graded

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Modeling the behavior of bilayer shape memory alloy/functionally graded material beams considering asymmetric shape memory alloy response

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x19880005 ◽

2019 ◽

Vol 31 (1) ◽

pp. 84-99 ◽

Cited By ~ 1

Author(s):

Nguyen Van Viet ◽

Wael Zaki ◽

Rehan Umer ◽

Quan Wang

Keyword(s):

Shape Memory Alloy ◽

Shape Memory ◽

Functionally Graded Material ◽

Three Dimensional ◽

Laminated Composite ◽

Alloy Layer ◽

Functionally Graded ◽

Tension And Compression ◽

Graded Material ◽

Asymmetric Shape

A new model is proposed to describe the response of laminated composite beams consisting of one shape memory alloy layer and one functionally graded material layer. The model accounts for asymmetry in tension and compression of the shape memory alloy behavior and successfully describes the dependence of the position of the neutral surface on phase transformation within the shape memory alloy and on the load direction. Moreover, the model is capable of describing the response of the composite beam to both loading and unloading cases. In particular, the derivation of the equations governing the behavior of the beam during unloading is presented for the first time. The effect of the functionally graded material gradient index and of temperature on the neutral axis deviation and on the overall behavior of the beam is also discussed. The results obtained using the model are shown to fit three-dimensional finite element simulations of the same beam.

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