scholarly journals Mechanical Properties of NiTi-TiC Shape-Memory Composites

1996 ◽  
Vol 459 ◽  
Author(s):  
D. C. Dunand ◽  
K. L. Fukami-Ushiro ◽  
D. Mari ◽  
J. A. Roberts ◽  
M. A. Bourke
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Neutron Diffraction ◽  
Mechanical Behavior ◽  
Shape Memory ◽  
Thermal Recovery ◽  
Shape Memory Composites ◽  
Compressive Testing ◽  
Tic Particulates ◽  
Elastic Particles

ABSTRACTThis paper reviews recent work on the mechanical behavior of martensitic NiTi composites reinforced with 10–20 vol.% TiC particulates. The behavior of the composites is compared to that of unreinforced NiTi, so as to elucidate the effect of mismatch due to matrix transformation, thermal expansion, twinning or slip, in the presence of purely elastic particles. The twinning and subsequent thermal recovery of deformed composites, measured both macroscopically (by compressive testing and by dilatometry) and microscopically (by neutron diffraction), are summarized.

scholarly journals Shape Memory Behavior of Carbon Black-reinforced Trans-1,4-polyisoprene and Low-density Polyethylene Composites

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 807 ◽  
Author(s):  
Lin Xia ◽  
Han Gao ◽  
Weina Bi ◽  
Wenxin Fu ◽  
Guixue Qiu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Shape Memory ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Shape Memory Behavior ◽  
Blending Method ◽  
Shape Memory Properties ◽  
Shape Memory Composites ◽  
Properties Of Composites

Shape memory composites of trans-1,4-polyisoprene (TPI) and low-density polyethylene (LDPE) with easily achievable transition temperatures were prepared by a simple physical blending method. Carbon black (CB) was introduced to improve the mechanical properties of the TPI/LDPE composites. The mechanical, cure, thermal and shape memory properties of the TPI/LDPE/CB composites were investigated in this study. In these composites, the crosslinked network generated in both the TPI and LDPE portions acted as a fixed domain, while the crystalline regions of the TPI and LDPE portions acted as a reversible domain in shape memory behavior. We found the mechanical properties of composites were promoted significantly with an increase of CB content, accompanied with the deterioration of shape memory properties of composites. When CB dosage was 5 parts per hundred of rubber composites (phr), best shape memory property of composites was obtained with a shape fixity ratio of 95.1% and a shape recovery ratio of 95.0%.

scholarly journals Mechanical properties of NiTi and CuNiTi shape-memory wires used in orthodontic treatment. Part 1: stress-strain tests

2013 ◽  
Vol 18 (4) ◽  
pp. 35-42 ◽  
Author(s):  
Marco Abdo Gravina ◽  
Ione Helena Vieira Portella Brunharo ◽  
Cristiane Canavarro ◽  
Carlos Nelson Elias ◽  
Cátia Cardoso Abdo Quintão
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Shape Memory ◽  
Orthodontic Treatment ◽  
Testing Machine ◽  
The Other ◽  
Lower Percentage ◽  
Machine Model ◽  
Military Institute ◽  
The Military

OBJECTIVE: This research aimed to compare, through traction tests, eight types of superelastic and heat-activated NiTi archwires, by six trade companies (GAC, TP, Ormco, Masel, Morelli and Unitek) to those with addition of copper (CuNiTi 27ºC and 35ºC, Ormco). METHODS: The tests were performed in an EMIC mechanical testing machine, model DL10000, capacity of 10 tons, at the Military Institute of Engineering (IME). RESULTS: The results showed that, generally, heat-activated NiTi archwires presented slighter deactivation loadings in relation to superelastic. Among the archwires that presented deactivation loadings biologically more adequate are the heat-activated by GAC and by Unitek. Among the superelastic NiTi, the CuNiTi 27ºC by Ormco were the ones that presented slighter deactivation loadings, being statistically (ANOVA) similar, to the ones presented by the heat-activated NiTi archwires by Unitek. When compared the CuNiTi 27ºC and 35ºC archwires, it was observed that the 27ºC presented deactivation forces of, nearly, ⅓ of the presented by the 35ºC. CONCLUSION: It was concluded that the CuNiTi 35ºC archwires presented deactivation loadings biologically less favorable in relation to the other heat-activated NiTi archwires, associated to lower percentage of deformation, on the constant baselines of deactivation, showing less adequate mechanical behavior, under traction, in relation to the other archwires.

scholarly journals Mechanical properties of NiTi-TiC shape-memory composites

1997 ◽  
Author(s):  
D.C. Dunand ◽  
K.L. Fukami-Ushiro ◽  
D. Mari ◽  
J.A. Roberts ◽  
M.A. Bourke
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Shape Memory Composites

Electro-thermo-mechanical behavior of carbon nanopaper shape memory polymer composites

2021 ◽  
pp. 1045389X2110188
Author(s):  
Veli Bugra Ozdemir ◽  
Kawai Kwok
Keyword(s):  
Mechanical Behavior ◽  
Shape Memory ◽  
Shape Change ◽  
Shape Memory Polymer ◽  
Axial Loading ◽  
Element Model ◽  
Close Correlation ◽  
Stimuli Responsive ◽  
Shape Memory Composites ◽  
Shape Programming

An electro-active composite based on carbon nanopaper (CNP) shape memory polymer (SMP) composite is proposed for actuating deployment of composite deployable structures. Carbon nanopaper shape memory composites are stimuli-responsive materials that can change between programmed shapes and the original shape by a voltage input. The proposed composite is a sandwich structure where the CNP layer acts as a flexible electrical heater when a voltage difference is applied. The shape change behavior of CNP-SMP composite presents a coupled electrical-thermal-structural problem. This paper presents a combined experimental, numerical, and analytical study of the time-dependent shape programming, stowage, and actuation of the CNP-SMP composite. The governing equations for the multiphysics behavior are derived. Characterization of the electrical and mechanical properties of the materials are carried out and employed in a nonlinear, fully coupled electrical-thermal-structural finite element model. Shape programming, stowage and actuation characteristics of the composite are investigated experimentally under axial loading. An analytical model is derived for the thermo-mechanical behavior of the composite which directly expresses the recovery over time through the creep compliance function. Close correlation is obtained between experimental measurements and numerical simulations. The proposed model can accurately predict the load and shape characteristics throughout programming, stowage, and actuation.

Shape recovery characteristics of shape memory cyanate ester/epoxy composite reinforced with calcium sulfate whisker

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yongkun Wang ◽  
Yuting Zhang ◽  
Jinhua Zhang ◽  
Junjue Ye ◽  
Wenchao Tian
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Calcium Sulfate ◽  
High Performance ◽  
Shape Recovery ◽  
Bending Strength ◽  
Cyanate Ester ◽  
Content Type ◽  
Shape Memory Composites ◽  
Calcium Sulfate Whiskers

Purpose The purpose of this paper is to study the influence of calcium sulfate whiskers (CSWs) on the thermodynamic properties and shape memory properties of epoxy/cyanate ester shape memory composites. Design/methodology/approach To improve the mechanical properties of shape memory cyanate ester (CE)/epoxy polymer (EP) resin, high performance CSWs were used to reinforce the thermo-induced shape memory CE/EP composites and the shape memory CSW/CE/EP composites were prepared by molding. The effect of CSW on the mechanical properties and shape memory behavior of shape memory CE/EP composites was investigated. Findings After CSW filled the shape memory CE/EP composites, the bending strength of the composites is greatly improved. When the content of CSW is 5 Wt.%, the bending strength of the composite is 107 MPa and the bending strength is increased by 29 per cent compared with bulk CE/EP resin. The glass transition temperature and storage modulus of the composites were improved in CE/EP resin curing system. However, when the content of CSW is more than 10 Wt.%, clusters are easily formed between whiskers and the voids between whiskers and matrix increase, which will lead to the decrease of mechanical properties of composites. The results of shape memory test show that the shape memory recovery time of the composites decreases with the decrease of CSW content at the same temperature. In addition, the shape recovery ratio of the composites decreased slightly with the increase of the number of thermo-induced shape memory cycles. Research limitations/implications A simple way for fabricating thermo-activated SMP composites has been developed by using CSW. Originality/value The outcome of this study will help to fabricate the SMP composites with high mechanical properties and the shape memory CSW/CE/EP composites are expected to be used in space deployable structures.

scholarly journals Facile Fabrication of Eucommia Rubber Composites with High Shape Memory Performance

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3479
Author(s):  
Lin Xia ◽  
Jiafeng Meng ◽  
Yuan Ma ◽  
Ping Zhao
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Memory Performance ◽  
Analytical Techniques ◽  
Cross Linking ◽  
Rubber Composites ◽  
Restoring Force ◽  
Shape Memory Composites ◽  
Facile Fabrication ◽  
Properties Of Materials

We processed a series of shape memory Eucommia rubber (ER) composites with both carbon–carbon and ionic cross-linking networks via a chemical cross-linking method. The influence of the carbon–carbon cross-linking and ion cross-linking degree of ER composites on curing, mechanical, thermal, and shape memory properties were studied by DSC, DMA, and other analytical techniques. Dicumyl peroxide (DCP) and zinc dimethacrylate (ZDMA) played a key role in preparing ER composites with a double cross-linking structure, where DCP initiated polymerization of ZDMA, and grafted ZDMA onto polymer molecular chains and cross-linked rubber molecular chains. Meanwhile, ZDMA combined with rubber macromolecules to build ionic cross-linking bonds in composites under the action of DCP and reinforced the ER composites. The result showed that the coexistence of these two cross-linking networks provide a sufficient restoring force for deformation of shape memory composites. The addition of ZDMA not only improved the mechanical properties of materials, but also significantly enhanced shape memory performance of composites. In particular, Eucommia rubber composites exhibited outstanding mechanical properties and shape memory performance when DCP content was 0.2 phr.

Shape Recovery and Mechanical Properties of Shape Memory Composites

2008 ◽  
Author(s):  
Christina N. Yarborough ◽  
Emily M. Childress ◽  
Richard K. Kunz
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Past Research ◽  
Tensile Tests ◽  
Synthetic Fiber ◽  
Carbon Fiber Composites ◽  
Fiber Volume ◽  
Shape Memory Composites

As the need for deployable space structures continues to increase, a deeper understanding of the mechanical properties and the responses of shape memory composites will be needed. Past research efforts have been focused on woven (0/90) carbon fiber composites which limit the shape memory capabilities due to the brittle nature of this fiber. The current work not only utilizes a synthetic fiber which allowed for a greater versatility in the composite, but also investigates the effects of angle plies and fiber volume fraction on the attainable bend ratio of the laminates. Four types of laminates were made to test the effects of laminate thickness, angle-plies, and fiber volume fraction. The specimens from these laminates were placed in both bending and tensile tests to investigate the effect of the fiber reinforcement on the polymer’s stiffness, strength and recovery. Testing revealed that the thicker specimens demonstrated improved recovery over the thinner samples, and that the angle-ply specimens recovered better than the (0/90) specimens. The recovery of the (0/90) specimens was improved by increasing the fiber volume fraction. Most significantly, the specimens were able to achieve smaller bend ratios than in previous studies without fiber microbuckling or fiber breakage. The tensile test data revealed that the bending cycles had little to no affect on the material properties of the composite. Only the modulus of the 5-ply (0/90) was seen to slightly decrease as the bending ratio decreased.

MODELISATION DE L'INFLUENCE DU TRAITEMENT THERMIQUE SUR LES PROPRIETES MECANIQUES DES ALLIAGES ALUMINIUM-CUIVRE (Al-Cu)

2015 ◽  
Vol 10 (2) ◽  
pp. 2753-2761
Author(s):  
Saad El Madani ◽  
S. ELHAMZI ◽  
A. IBNLFASSI ◽  
L. ZERROUK ◽  
O. BEN LENDA ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Solidification Process ◽  
Traitement Thermique ◽  
Homogenization Process ◽  
Fundamental Reason ◽  
Segregation Phenomenon ◽  
Proprietes Mecaniques ◽  
Cooling Velocity ◽  
Copper Effect

In order to master and improve the quality and properties of the final products, the major industrial challenge lies in the possibility of controlling the morphology, size of microstructures that reside within the molded pieces, as well as their defects; this is the fundamental reason according to which we are more and more interested in mastering the growth and germination of such alloys, as well as the developing structures, at the time of solidification process. The modeling reveals as a valuable aid in the mastery of the formation of such heterogeneousness: segregation cells that are incompatible with industrial requirements.   The whole work focuses upon the modeling of the segregation phenomenon of the four hypoeutectic alloys, Al1%Cu, Al2%Cu, Al3%Cu et Al4%Cu, as well as the copper effect upon certain mechanical properties of aluminum. Usually, the microstructure and mechanical behavior of such alloys as Al-Cu are directly influenced by some parameters such as composition, cooling velocity and homogenization process.

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