Room temperature deformable shape memory composite with fine-tuned crystallization induced via nanoclay particles

2017 ◽  
Vol 55 (16) ◽  
pp. 1197-1206 ◽  
Author(s):  
Yu-Chen Sun ◽  
Shenyang Cai ◽  
Jie Ren ◽  
Hani E. Naguib
Keyword(s):  
Shape Memory ◽  
Room Temperature ◽  
Shape Memory Composite

A composite material with room temperature shape processability and optical repair

2016 ◽  
Vol 4 (25) ◽  
pp. 5932-5939 ◽  
Author(s):  
Guo Li ◽  
Hu Zhang ◽  
Daniel Fortin ◽  
Weizheng Fan ◽  
Hesheng Xia ◽  
...  
Keyword(s):  
Composite Material ◽  
Shape Memory ◽  
Room Temperature ◽  
Ambient Conditions ◽  
Shape Memory Composite

The room temperature programmability of a shape memory composite material enables the optical repair of deformation damage under ambient conditions.

Forming of Shape Memory Composite Structures

2013 ◽  
Vol 554-557 ◽  
pp. 1930-1937 ◽  
Author(s):  
Loredana Santo ◽  
Fabrizio Quadrini ◽  
Leonardo De Chiffre
Keyword(s):  
Shape Memory ◽  
Composite Structures ◽  
Room Temperature ◽  
Thermoplastic Composite ◽  
Bending Test ◽  
Core Material ◽  
Foam Core ◽  
Axial Tomography ◽  
Initial Shape ◽  
Shape Memory Composite

A new forming procedure was developed to produce shape memory composite structures having structural composite skins over a shape memory polymer core. Core material was obtained by solid state foaming of an epoxy polyester resin with remarkably shape memory properties. The composite skin consisted of a two-layer unidirectional thermoplastic composite (glass filled polypropylene). Skins were joined to the foamed core by hot compression without any adhesive: a very good adhesion was obtained as experimental tests confirmed. The structure of the foam core was investigated by means of computer axial tomography. Final shape memory composite panels were mechanically tested by three point bending before and after a shape memory step. This step consisted of a compression to reduce the panel thickness up to 60%. At the end of the bending test the panel shape was recovered by heating and a new memory step was performed with a higher thickness reduction. Memory steps were performed at room temperature and 120 °C so as to test the foam core in the glassy and rubbery state, respectively. Shape memory tests revealed the ability of the shape memory composite structures to recover the initial shape also after severe damaging (i.e. after room temperature compression). Compressing the panel at a temperature higher than the foam resin glass transition temperature minimally affects composite stiffness.

High performance shape memory effect in nitinol wire for actuators with increased operating temperature range

2014 ◽  
Vol 07 (05) ◽  
pp. 1450063 ◽  
Author(s):  
Riccardo Casati ◽  
Carlo Alberto Biffi ◽  
Maurizio Vedani ◽  
Ausonio Tuissi
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
High Performance ◽  
Room Temperature ◽  
Operating Temperature ◽  
Niti Wire ◽  
Shape Memory Actuators ◽  
Nitinol Wire ◽  
Operating Temperature Range

In this research, the high performance shape memory effect (HP-SME) is experimented on a shape memory NiTi wire, with austenite finish temperature higher than room temperature. The HP-SME consists in the thermal cycling of stress induced martensite and it allows achieving mechanical work higher than that produced by conventional shape memory actuators based on the heating/cooling of detwinned martensite. The Nitinol wire was able to recover about 5.5% of deformation under a stress of 600 MPa and to withstand about 5000 cycles before failure. HP-SME path increased the operating temperature of the shape memory actuator wire. Functioning temperatures higher than 100°C was reached.

Conceptual Design of an Experiment for the International Space Station About Shape Memory Composite in Space Environment

2017 ◽  
Author(s):  
Loredana Santo ◽  
Denise Bellisario ◽  
Giovanni Matteo Tedde ◽  
Fabrizio Quadrini
Keyword(s):  
Shape Memory ◽  
International Space Station ◽  
Space Station ◽  
Sun Exposure ◽  
Aging Effect ◽  
Space Environment ◽  
Aging Effects ◽  
Solar Sails ◽  
International Space ◽  
Shape Memory Composite

Shape memory polymers (SMP) and composites (SMPC) may be used for many applications in Space, from self-deployable structures (such as solar sails, panels, shields, booms and antennas), to grabbing systems for Space debris removal, up to new-concept actuators for telescope mirror tuning. Experiments on the International Space Station are necessary for testing prototypes in relevant environment, above all for the absence of gravity which affects deployment of slender structures but also to evaluate the aging effects of the Space environment. In fact, several aging mechanisms are possible, from polymer cracking to cross-linking and erosion, and different behaviors are expected as well, from consolidating the temporary shape to composite degradation. Evaluating the possibility of shape recovery because of sun exposure is another interesting point. In this study, a possible experiment on the ISS is shown with the aim of evaluating the aging effect of Space on material performances. The sample structure is described as well as the testing strategy.

Cold Bending a Ni-Ti Shape Memory Alloy Wire

2015 ◽  
Vol 661 ◽  
pp. 98-104 ◽  
Author(s):  
Kuang-Jau Fann ◽  
Pao Min Huang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Room Temperature ◽  
Aging Treatment ◽  
Treatment Temperature ◽  
Bending Test ◽  
Solution Treatment Temperature

Because of being in possession of shape memory effect and superelasticity, Ni-Ti shape memory alloys have earned more intense gaze on the next generation applications. Conventionally, Ni-Ti shape memory alloys are manufactured by hot forming and constraint aging, which need a capital-intensive investment. To have a cost benefit getting rid of plenty of die sets, this study is aimed to form Ni-Ti shape memory alloys at room temperature and to age them at elevated temperature without any die sets. In this study, starting with solution treatments at various temperatures, which served as annealing process, Ni-rich Ni-Ti shape memory alloy wires were bent by V-shaped punches in different curvatures at room temperature. Subsequently, the wires were aged at different temperatures to have shape memory effect. As a result, springback was found after withdrawing the bending punch and further after the aging treatment as well. A higher solution treatment temperature or a smaller bending radius leads to a smaller springback, while a higher aging treatment temperature made a larger springback. This springback may be compensated by bending the wires in further larger curvatures to keep the shape accuracy as designed. To explore the shape memory effect, a reverse bending test was performed. It shows that all bent wires after aging had a shape recovery rate above 96.3% on average.

Fabrication of an Apatite/Collagen Composite Coating on the NiTi Shape Memory Alloy through Electrochemical Deposition and Coating Characterisation

2009 ◽  
Vol 618-619 ◽  
pp. 319-323 ◽  
Author(s):  
Parama Chakraborty Banerjee ◽  
Tao Sun ◽  
Jonathan H.W. Wong ◽  
Min Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Coating ◽  
Electrochemical Deposition ◽  
Room Temperature ◽  
Composite Coatings ◽  
Deposition Process ◽  
Niti Shape Memory Alloy ◽  
X Ray ◽  
Niti Sma

To improve the biocompatibility and bioactivity of NiTi shape memory alloy (SMA), apatite/collagen composite coatings were fabricated on the surface of NiTi SMA at room temperature using the electrochemical deposition technique. Spherical apatite particles and fibrous collagen that formed the composite coating were visible under scanning electron microscope (SEM). The Ca/P ratio of the apatite component in the coating, as determined by energy dispersive X-ray spectroscopy (EDX), was about 1.38 which is slightly higher than that of octocalcium phosphate (OCP). X-ray diffraction result showed that the apatite was amorphous, which was due to the low temperature (i.e., room temperature) deposition process. The structure of the composite coatings was further characterized using Fourier transform infrared reflection spectroscopy (FTIR). It was also found that, compared to bare NiTi SMA samples, the wettability of as-deposited samples was increased because of the formation of the composite coating.

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