Experimental investigation and 3-D modeling of rate-dependent irrecoverable deformation in shape memory alloys

2009 ◽  
Author(s):  
Darren J. Hartl ◽  
Dimitris C. Lagoudas
Keyword(s):  
Experimental Investigation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Rate Dependent

scholarly journals Experimental Investigation of the Mechanisms and Performance of Active Auxetic and Shearing Textiles

2019 ◽  
Author(s):  
Rachael Granberry ◽  
Brad Holschuh ◽  
Julianna Abel
Keyword(s):  
Experimental Investigation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Smart Materials ◽  
Haptic Feedback ◽  
Axial Stress ◽  
The Body ◽  
Strain Behavior ◽  
Biaxial Tensile Testing ◽  
And Performance

Abstract Anisotropic textiles are commonly used in wearable applications to achieve varied bi-axial stress-strain behavior around the body. Auxetic textiles, specifically those that exhibit a negative Poisson’s ratio (v), likewise exhibit intriguing behavior such as volume increase in response to impact or variable air permeability. Active textiles are traditional textile structures that integrate smart materials, such as shape memory alloys, shape memory polymers, or carbon nanotubes, to enable spatial actuation behavior, such as contraction for on-body compression or corrugation for haptic feedback. This research is a first experimental investigation into active auxetic and shearing textile structures. These textile structures leverage the bending- and torsional-deformations of the fibers/filaments within traditional textile structures as well as the shape memory effect of shape memory alloys to achieve novel, spatial performance. Five textile structures were fabricated from shape memory alloy wire deformed into needle lace and weft knit textile structures. All active structures exhibited anisotropic behavior and four of the five structures exhibited auxetic behavior upon free recovery, contracting in both x- and y-axes upon actuation (v = −0.3 to −1.5). One structure exhibited novel shearing behavior, with a mean free angle recovery of 7°. Temperature-controlled biaxial tensile testing was conducted to experimentally investigate actuation behavior and anisotropy of the designed structures. The presented design and performance of these active auxetic, anisotropic, and shearing textiles inspire new capabilities for applications, such as smart wearables, soft robotics, reconfigurable aerospace structures, and medical devices.

scholarly journals A New Rate-Dependent Constitutive Model of Superelastic Shape Memory Alloys and Its Simple Application in a Special Truss Moment Frame Simulation

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Maria I. Ntina ◽  
Dimitrios S. Sophianopoulos
Keyword(s):  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Experimental Results ◽  
Simple Application ◽  
Moment Frame ◽  
Rate Dependent ◽  
Ongoing Work ◽  
Good Agreement

In this work, a new constitutive model of the behavior of shape-memory alloys is presented, based on earlier models, showing a very good agreement with the existing experimental results. A simple approximate application concerning the use of these alloys modelled as dissipation devices in a special truss-moment frame is demonstrated. The results obtained are considered sufficiently encouraging as a motivation for the ongoing work.

Effect of microstructural phases on thermo-mechanical analysis of ductile Cu–Al–Mn–Ni memory alloys for structural applications

2020 ◽  
Vol 10 (8) ◽  
pp. 1337-1345
Author(s):  
Tareq Manzoor ◽  
Muhammad Zafar ◽  
Muddassir Ali ◽  
Mahmood Saleem ◽  
Woo Young Kim
Keyword(s):  
Experimental Investigation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Strain Energy ◽  
Mechanical Analysis ◽  
Absorption Capacity ◽  
Damping Properties ◽  
Structural Applications ◽  
Nickel Addition ◽  
Compositional Variations

In this present study, the particulars of an experimental investigation on the effect of nickel addition on microstructural, strain recovery and strain absorption capacity of ternary (Cu–Al–Mn) shape memory alloys has been deliberated. Six dissimilar compositions with varying amounts of Ni in (Cu–Al–Mn) shape memory alloys have been synthesized and investigated to measure their potential for structural applications. Microstructural and detailed phase analysis has been studied. Additions of Ni have enhanced the tensile strength of these alloys. These compositional variations have influenced shape memory and damping properties in from of dissipated strain energy as well as the super elasticity of the alloys.

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