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Showing 1 to 20 of 51 for “"shape memory effect"”.
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Domain structure, phase transformation, mechanical behavior and shape memory effect in a rare-earth orthoniobate lanthanum niobate
… the rubberlike behavior and (4) exploring the shape memory effect in polycrystal ceramic LaNbO$\sb4$."
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An experimental investigation of the behavior of Nitinol
Shape memory alloys (SMA) have the unique ability to recover large strains and generate large recovery stresses via a repeatable martensitic transformation. Stress-strain and shape memory effect characteristics are needed in order to develop SMA force actuator design methods. Moreover, constitutive …
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Modeling of materials with internal variables using a thermomechanical approach
… constitutive model for the two-way shape memory effect and a one-dimensional constitutive model for piezoceramics have been developed, respectively. In modeling the two-way shape memory effect, a residual stress σ<sub>re</sub> is introduced as a controlling parameter for the two-way …
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The effect of annealing on the microstructure of Cu-Al-Ni-Mn shape memory alloy microwires
Shape memory alloys exhibit superelasticity and the shape memory effect by undergoing a diffusionless phase transformation between the austenite and martensite phases. Nickel-titanium alloys are currently the most common material used. However, due to their expensive cost, alternatives such as …
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Effect of the Mn Additive on Cu-Zn-Al Shape Memory Alloy
… status in the research field of copper-based shape memory alloys including the Cu-Al-Ni, Cu-Zn-Al, Cu-Al-Mn, Cu-Al-Be, and other copper-based shape memory alloy. From the standpoint of mechanisms (phase transformation, thermodynamics) and properties (shape memory effect, mechanical …
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Prestressing Concrete with Shape Memory Alloy Fibers
… large, straight members. During the last decade, shape memory alloys (SMA) have become more prevalent in engineering and civil engineering applications. The shape memory effect refers to the contraction of the SMA when it is heated to its austenite phase. When a prestrain is induced in the SMA, it …
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An Investigation of the Structural and Magnetic Transitions in Ni-Fe-Ga Ferromagnetic Shape Memory Alloys
… transformations in Ni-Fe-Ga ferromagnetic shape memory alloys are very sensitive to both alloy chemistry and thermal history. A series of Ni-Fe-Ga alloys near the prototype Heusler composition (X2YZ) were fabricated and homogenized at 1423 °K, and a Ni₅₃Fe₁₉Ga₂₈ alloy was subsequently …
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A Novel Shape Memory Behavior of Single-crystalline Metal Nanowires
… method (EAM) potentials are used. A novel shape memory effect and pseudoelastic behavior of single-crystalline FCC metal (Cu, Ni, and Au) nanowires are discovered. Specifically, upon tensile loading and unloading, these wires can recover elongations of up to 50%, well beyond the recoverable …
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Cu-based shape memory microwires : towards complex structures
Shape memory alloys are a distinctive type of material that exhibits the fascinating properties of the shape memory effect and superelasticity. Shape memory properties are characterized by the diffusionless phase transformation between austenite and martensite that can be thermally or stress …
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Temperature and Water Responsive Shape Memory Polymers for Soft Tissue Expansion
A biodegradable thermoplastic shape memory polymer which can be used for 3D printing patient specific soft tissue expanders was synthesized and characterized. The bottlebrush polymer with Poly (vinyl alcohol) backbone and polyurethane side chains exhibited shape memory effect. Using an …
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The preparation and characterization of thermo-sensitive colored hydrogel film and surfactant-free porous polystyrene three-dimensional network.
… and casting the polymers onto glass. The shape-memory effect has been observed when changing the environmental temperature. The temperature-dependent of turbidity of polymer hydrogel film was measured by HP UVVisible spectrophotometer. This intelligent hydrogel might be used in …
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The Characterization and Control of Shape Memory Alloy Cables for Reinforcement of Engineered Cementitious Composite Beams
… composite (ECC) beams using superelastic Nitinol shape memory alloy (SMA) cables. Nitinol is the most popularly used SMA and superelastic Nitinol cable possesses many attractive features, such as large recoverable strain, large load bearing capacity, among others. To understand the characteristics …
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The constitutive modeling of shape memory alloys
… thermomechanical constitutive model for shape memory alloys based on basic concepts of thermodynamics and phase transformation kinetics. Compared with other developed constitutive relations, this thermomechanical constitutive relation not only reflects the physical essence of shape memory …
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An exploration of shape memory polymers and (nano) composites for packaging applications.
Shape memory polymers, SMP, are gaining considerable interest in research and industry due to their novel properties and vast potential. SMP belong to an emerging class of materials known as 'smart polymers', and have the intriguing ability to be moulded into a temporary shape, store that temporary …
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PU elastomers and grafted GO/PU nanocomposite with self-healing and self-adapting capabilities for next-generation electrical insulation
… using reversible hydrogen bonding network and shape memory effect. By further grafting two dimensional graphene oxide (GO) nanosheets as the conductive backbone and regulating the concentration of nanoparticles and their interfacial states, it was shown that the GO/PU composites have excellent …
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Reduced-Order Modeling and Design Optimization of Thermomechanical Shape Memory Alloy-Based Bistable Microactuators and Hyperelastic Material Systems
… modeling complex material behavior, focusing on shape memory alloys (SMAs) and hyperelastic materials. The goal is to improve both prediction accuracy and computational efficiency in simulations used for designing advanced materials and bistable microactuators. The work begins with a stabilized …
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Pulse-field actuation of collinear magnetic single crystals
Ferromagnetic shape memory alloys (FSMAs) are a class of alloys that exhibits the shape memory effect, as in the alloy nickel-titanium, sometimes known as Nitinol. In FSMAs, though, the shape changes are not brought on just by changes in temperature or mechanical stresses, but can also be driven by …
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Effects of composition and ausaging on microstructures and magnetic shape memory response of Fe-Ni-Co-Ti alloys
Magnetic Shape-Memory (MSM) materials are a new category of actuator materials with the potential to produce both large actuator strain and rapid response. To explore the possibility of developing MSM materials based on Fe-Ni-Co-Ti alloys, the effects of chemical composition (Co/Ni ratio) and …
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Cryogenic Shape Memory Alloy Actuators For Spaceport Technologies: Materials Characterization And Prototype Testing
Shape memory alloys (SMAs) possess the unique ability to change their shape by undergoing a solid-state phase transformation at a particular temperature. The shape change is associated with a large strain recovery as the material returns to its "remembered" shape. Their ability to act as both …
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Commissioning Of An Arc-melting/vacuum Quench Furnace Facility For Fabrication Of Ni-ti-fe Shape Memory Alloys, And The Characterization
Shape memory alloys when deformed can produce strains as high as 8%. Heating results in a phase transformation and associated recovery of all the accumulated strain, a phenomenon known as shape memory. This strain recovery can occur against large forces, resulting in their use as actuators. The …
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