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1
Content available Finite element analysis of a superelastic shape memory alloy considering the effect of plasticity
Jiang X., Li B.
Journal of Theoretical and Applied Mechanics
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2017
|
Vol. 55 nr 4
1355--1368
EN
In the present study, a shape memory alloy (SMA) phenomenological constitutive model is proposed that is capable of describing SMA superelastic behavior and the plasticity effect. The phase transformation constitutive model, by using strain and temperature as control variables to judge the phase transformation points in order to avoid the complexity of transformation correction, incorporates plasticity described by the von Mises isotropic hardening model. Further, the proposed model is implemented into the finite element package ANSYS by the user subroutine USERMAT. The results produced by the proposed model of simulated superelastic and plasticity behavior are compared with experimental data taken from the literature.
2
Content available remote Enhancement of bending fatigue life in TiNi shape-memory alloy tape by nitrogen ion implantation
Takeda K., Matsui R., Tobushi H., Homma S., Levintant-Zayonts N., Kucharski S.
Archives of Mechanics
|
2015
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Vol. 67, nr 4
293--310
EN
A shape-memory alloy (SMA) is expected to be applied as intelligent or smart material since it shows the functional characteristics of the shape memory effect and superelasticity. Most SMA elements, with these characteristics, perform cyclic motions. In these cases, the fatigue property of SMA is one of the most important issues in view of evaluating functional characteristics of SMA elements. The fatigue properties are complex since they depend on stress, strain, temperature and their hysteresis. If an SMA is implanted with high-energy ions, the thermomechanical properties of the material may change, resulting in long fatigue life. In the present study, the nitrogen ion implantation was applied to modify the surface of a TiNi SMA tape and the influence of implantation treatment on the bending fatigue properties was investigated.
3
Modelowanie efektu supersprężystości metodą elementów skończonych
Młocek B.
Modelowanie Inżynierskie
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2014
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T. 21, nr 52
132--139
PL
W pracy przedstawiono wyniki modelowania zjawiska supersprężystości metodą elementów skończonych. Przedyskutowano metodykę tworzenia modeli jednoosiowego rozciągania oraz trójpunktowego zginania. Analizę numeryczną prowadzono w środowisku obliczeniowym ANSYS 14.5. Wyznaczono wartości naprężeń normalnych w funkcji odkształcenia oraz wartości siły reakcji względem przemieszczenia belki ze stopu NiTi opisanej numerycznie. Uzyskane wyniki analiz numerycznych porównano z danymi eksperymentalnymi zamieszczonymi w pracy Auricchio i innych [1], uzyskując jakościowo dobrą zgodność. Użycie analiz numerycznych MES uzasadnione jest efektywną optymalizacją wytwarzania materiałów wykazujących efekt supersprężystości.
EN
The paper presents the results of modeling using finite element method superelastic phenomena occurring in shape memory alloys. The methodology for modeling uniaxial tensile and three-point bending was discussed. Numerical analysis was carried out in 14.5 ANSYS. The values of tensile stress as a function of strain and the force reaction in relation to displacement for the NiTi beam were shown. The obtained results were compared with good qualitatively agreement with experimental data given in work Auricchio et al [1]. Using finite element method in optimization of manufacturing materials in which occur the superelastic effect was shown.
4
Content available remote Influence of nitrogen ion implantation on deformation and fatigue properties of TiNi shape-memory alloy wire
Takeda K., Mitsui K., Tobushi H., Levintant-Zayonts N., Kucharski S.
Archives of Mechanics
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2013
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Vol. 65, nr 5
391--405
EN
A shape memory alloy (SMA) is expected to be applied as intelligent material since it shows the unique characteristics of the shape memory effect and superelasticity. Most SMA elements, with these characteristics, perform cyclic motions. In these cases, fatigue of SMA is one of the important properties in view of evaluating functional characteristics. The fatigue properties are complex since they depend on stress, strain, temperature and time. If SMA is implanted by high energy ions, the thermomechanical properties may change, resulting in long fatigue life. In the present study, the nitrogen ion implantation was applied to modify TiNi SMA wire surface and the influence of implantation treatment on the tensile deformation and bending fatigue properties was investigated.
5
Content available remote Creep and creep recovery under stress-controlled subloop loading in TiNi shape memory alloy
Takeda K., Matsui R., Tobushi H., Pieczyska E. A.
Archives of Mechanics
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2013
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Vol. 65, nr 5
429-444
EN
If a shape memory alloy (SMA) is subjected to the subloop loading under the stress-controlled condition, creep and creep recovery can appear based on the martensitic transformation. In the design of SMA elements, these deformation properties are important since the deflection of SMA elements can change under constant load. The conditions for the progress of the martensitic transformation are discussed based on the kinetics of the martensitic transformation for the SMA. The creep deformation properties are investigated experimentally for TiNi SMA. The creep strain rate increases in proportion to the martensitic transformation strain; the creep recovery strain rate increases in proportion to the reverse transformation strain.
6
Wpływ wyżarzania po przeróbce plastycznej na zimno na przemiany fazowe i właściwości drutów TiNiCo przeznaczonych na implanty medyczne
Lekston Z., Stróż D., Bierska-Piech B., Jędrusik-Pawłowska M., Żaworonkow D.
Inżynieria Materiałowa
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2012
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Vol. 33, nr 3
206--209
PL
Stopy Ti-Ni wykazujące jedno- i dwukierunkową pamięć kształtu oraz supersprężystość są z powodzeniem wykorzystywane w różnych zastosowaniach medycznych. Rodzaj i kinetyka przemian fazowych oraz właściwości funkcjonalne tych stopów modyfikuje się przez dobór składu chemicznego i zastosowanie odpowiedniej technologii przeróbki plastycznej oraz obróbki cieplnej. Wprowadzenie kobaltu zamiast niklu (ok. 3% at.) poprawia właściwości plastyczne stopów i ułatwia ich przeróbkę plastyczną na zimno. W pracy określono wpływ temperatury wyżarzania przez 15 minut w zakresie temperatury 300÷700°C na przemiany fazowe i efekty pamięci kształtu drutów Ti50Ni48,7Co1,3 przeciąganych na zimno. Metodą rentgenografii temperaturowej i DSC stwierdzono, że przemiany fazowe w badanym stopie zachodzą odwracalnie z udziałem pośredniej fazy romboedrycznej R. Obecność fazy R potwierdzono metodą transmisyjnej mikroskopii elektronowej. Wyniki prób zginania drutów i swobodnego odzysku kształtu prowadzone zgodnie z normą ASTM F 2082-06 pozwoliły stwierdzić, że podczas nagrzewania druty całkowicie odzyskują kształt w temperaturze poniżej 40°C. Duże odkształcenie na zimno i wyżarzanie w temperaturze 450 i 500°C pozwoliło uzyskać dobre właściwości supersprężyste drutów. W próbie rozciągania cyklicznego i trójpunktowego zginania w zakresie odkształcania drutu do ok. 8% obserwowano wyraźne pętle supersprężystości. Z tych drutów przygotowano klamry do zespoleń złamań kostnych oraz spinki do anastomozy jelit dla sprawdzenia ich funkcjonalności w badaniach eksperymentalnych.
EN
Titanium-nickel alloys with one- and two-way shape memory and superelasticity effects have been successfully used in various medical applications. The course of phase transformations and functional properties can be modified by selection of the chemical composition and application of plastic working technology and heat treatment. The addition of cobalt for nickel in amounts up to about 3 at. % improves the plastic properties of alloys and facilitates the cold plastic working of alloys. In this work, the influence of the annealing temperature for 15 minutes in the temperature range 300÷700°C on the phase transformations and shape memory effects of cold drawn Ti50Ni48.7Co1.3 wires was studied. By X-temperature diffraction and the DSC method it was found that the phase transitions in the examined wires proceeded in a reversible manner and are accompanied by the precipitation of a rhombohedral R phase. The presence of the R-phase in selected samples was confirmed by transmission electron microscopy. In the tests of wires bending and free shape recovery carried out according to standard ASTM F 2082-06, it was found that during the heating wires fully recovered the shape at temperature below 40°C. After a strong cold deformation and annealing at 450 and 500°C, very good superelastic properties were induced in the wires. In the cyclic tensile and three-point bending tests in the deformation range up to about 8%, explicit superelastic loops were observed. From the wires after selected treatment, staples for joining bone fractures and clips for bowel anastomosis clips were prepared to verify their functionality in experimental studies.
7
Content available Supersprężyste zachowanie drutów NiTi podczas zginania
Lekston Z., Lacki P.
Engineering of Biomaterials
|
2012
|
Vol. 15, no. 116-117 spec. iss.
69--72
PL
W pracy przedstawiono supersprężyste właściwości drutów NiTi badane w testach rozciągania i zginania. Druty te użyto do przygotowania klamer do zespoleń złamań kości twarzy oraz sprężyn do plastyki czaszki. Przy projektowaniu implantów zastosowano modelowanie odkształcania metodą elementów skończonych. Uzyskano dobrą korelację krzywych symulowanych przy użyciu programu Adina z krzywymi eksperymentalnymi uzyskanymi podczas cyklicznego, trójpunktowego zginania drutów oraz dystraktorów czaszkowych. Wprowadzenie do programu odpowiednich parametrów charakteryzujących badane materiały umożliwi obliczanie wielkości naprężeń zredukowanych i odkształceń oraz ułatwi projektowanie wymaganych własności implantów o bardziej złożonych kształtach.
EN
The paper presents the superelastic properties of NiTi wires tested in tensile and bending tests. These wires were used to prepare staples for fixation bone fracture of the face and skull springs. In implants' designing the finite element modeling method was used for determining the deformation. A good correlation between simulated curves taken from ADINA System and experimental curves received in cyclic three-point bending wires was obtained. Making modifications to the ADINA system connected with relevant parameters, which characterize the investigated material, will enable establishing the size of reduced stresses and strains and facilitate the required properties of implants designing.
8
Content available Kształtowanie supersprężystych sprężyn NiTi do plastyki czaszki
Lekston Z.
Engineering of Biomaterials
|
2012
|
Vol. 15, no. 116-117 spec. iss.
33--36
PL
W pracy pokazano sposób przygotowania sprężyn NiTi w postaci prostych drutów, które po zamocowaniu w kształcie łuków na sklepieniu czaszki, w czasie leczenia kraniostenoz u dzieci działają ze stałą siłą w pożądanym zakresie odkształceń. Druty wykazujące supersprężystość uzyskano po przeciąganiu lub walcowaniu na zimno i wyżarzaniu w zakresie temperatur 400-500°C. Własności supersprężyste drutów sprawdzono w próbach rozciągania i trójpunktowego zginania. Z najlepszych drutów supersprężystych wykonano, prototypowe sprężynki do badań klinicznych i dobrano optymalne warunki kształtowania ich własności. Zarejestrowane w próbach trójpunktowego zginania krzywe zależności siły w funkcji ugięcia wykazują pożądane plateau podczas odciążania. Wykonane sprężyny podczas odciążania w pożądanym zakresie odkształceń 20-30 mm działają ze stałą siłą. Przygotowano typoszeregi sprężyn o różnych siłach oddziaływań w zakresie od kilku do około 10 N.
EN
The study shows how to prepare the NiTi springs in the form of straight wires which when attached in the shape of arcs to the vault of the skull operate with a constant force in the desired range of deformations during treatment of craniostenosis in children. Wires with superelastic properties were obtained after drawing or cold rolling and annealing in the temperature range of 400-500°C. Superelastic properties of the wires were tested in the tensile and three-point bending tests. The best superelastic wire was used to manufacture the prototype springs for clinical tests. Optimal conditions for developing their properties were selected. Force curves as a function of deflection registered during three-point bending tests show the desired plateau during unloading. During unloading in the desired range of deformations, i.e. 20-30 mm, the manufactured springs operate with a constant force. Series of types of springs with different interaction forces ranging from several to about 10 N were prepared.
9
Content available remote Functional warp-knitted fabrics with integrated superelastic NiTi filaments
Janouchova K., Heller L., Vysanska M.
Autex Research Journal
|
2012
|
Vol. 12, no. 2
34--39
EN
We report on a particular direction of currently conducted extended research on novel textiles with integrated thin metallic filaments made of an intermetallic shape memory NiTi alloy exhibiting functional behaviour such as superelastic deformation up to 10% and a thermally induced shape memory effect. Within this research direction we focus on development of single and multi-layered warp-knitted fabrics that are directionally reinforced with superelastic NiTi filaments. First, we describe the expected properties of such novel structures and their potential applications. Second, we present the functional thermomechanical behaviour of applied superelastic NiTi filaments. Third, we address questions related to the design and fabrication of warp-knitted fabrics with integrated NiTi filaments. Then, we describe experimental methods applied on novel functional textiles in order to evaluate their functional properties. Finally, we present and discuss results of experiments carried out on these novel functional textiles.
10
Content available remote Three-way actuation of shape memory composite
Tobushi H., Hayashi S., Pieczyska E., Date K., Nishimura Y.
Archives of Mechanics
|
2011
|
Vol. 63, nr 5-6
443-443
EN
The SMC belt composed of two kinds of SMAs with different phase transformation temperatures and SMP, was fabricated and the three-way (reciprocating) movement and recovery force in bending actuation were investigated. The results obtained can be summarized as follows. 1) The three-way bending movement was achived during heating and cooling, based on the characteristics of the SMA tapes and the SMP tape. 2) The recovery force decreased at first and increased thereafter during heating and decreased during cooling. The recovery force was roughly estimated by the proposed model. 3) The development and application of multi-functional SMCs with simple structure for three-dimensional actuators are highly expected.
11
Content available Non-associated superelasticity in rotating frame formulation
Vieille B., Boubakar M. L., Lexcellent C.
Journal of Theoretical and Applied Mechanics
|
2003
|
Vol. 41 nr 3
676-691
EN
In order to describe and predict the superelastic finite strains behaviour of Shape Memory Alloys, a kinematic description with directors is proposed. Compatible with either isotropic behaviours, it allows a direct extension from the small pertubation formalism. Particularly, a general framework is proposed for the description of the Shape Memory Alloys superelastic behaviour under 3D proportional loadings.
PL
W pracy przedstawiono metodę przewidywania i opisu stanu skończonych supersprężystych odkształceń określających zachowanie się stopów z pamięcią kształtu. Metodę oparto na reprezentacji kinematycznej stanu otrzymanej za pomocą wektorów kierunkowych. Metoda ta, jako spójna dla materiałów izotropowych i anizotropowych, umożliwia wnioskowanie wprost z formalizmu techniki perturbacyjnej bazującej na małym parametrze. W szczególności, zaproponowano ogólne podejście do opisu supersprężystego zachowania się stopów z pamięcią kształtu poddanych proporcjonalnym obciążeniom przestrzennym.
12
Content available remote Pseudoviscoelastic behavior of TiNi shape memory alloys under stress-controlled subloop loadings
Tobushi H., Endo M., Ikawa T., Shimada D.
Archives of Mechanics
|
2003
|
Vol. 55, nr 5-6
519-530
EN
The superelastic behavior of TiNi shape memory alloy under various subloop loadings were investigated. The results obtained can be summarized as follows. (1) In the case of subloop loading under strain-controlled conditions, the reloading curve passes through the unloading-start point. In the case of stress-controlled conditions, the return-point memory does not appear. (2) In the case of subloop loading under stress-controlled conditions, strain increases under constant stress in the loading process and decreases in the unloading process. (3) In the case of subloop loading under stress-controlled conditions, stress decreases under constant strain in the loading process and increases in the unloading process. (4) The above-mentioned behavior concerning the return-point memory and the pseudoviscoelastic behavior similar to creep and stress relaxation, appear according to the martensitic transformation and the reverse transformation based on the variation in stress and temperature.
13
Content available remote Development of shape memory alloy fabrics for composite structures
Boussu F., Bailleul G., Petitniot J. C., Vinchon H., Warneton D.
Autex Research Journal
|
2002
|
Vol. 2, no. 1
1--7
EN
Shape memory alloys (SMAs) are a unique class of alloys which are able both to 'remember' their shape at high temperature during their modification at lower temperature under their transition domain, and able to recover that initial shape when heated. This ability is known as the one-way shape memory effect. Moreover, SMAs present two other interesting properties, superelasticity and damping capabilities, which can be more or less combined with the first one. An SMA wire of Nitinol mesh was manufactured into technical fabric, in order to examine its weaving adaptability in comparison with a stainless wire and to investigate the different possibilities of use of the material inside composite structures. Several tests have been or will be carried out in order to check the effect of the weaving operation, and later to measure the efficiencies of damping and shape modification.
14
Content available remote Deformation behavior of TiNi shape-memory alloy under strain- or stress-controlled conditions
Tobushi H., Okumara K., Endo M., Tanaka K.
Archives of Mechanics
|
2002
|
Vol. 54, nr 1
75-91
EN
The deformation properties of TiNi shape-memory alloy subjected to strain control and stress control were investigated experimentally. The results obtained are summarized as follows. (1) In the case of a full loop, the stress-strain curves under stress-controlled conditions are similar to those under strain-controlled conditions with high strain rate. The overshoot and undershoot do not appear at the start points of the stress-induced martensitic transformation in these curves. (2) In the case of subloop under stress-controlled conditions, temperature decreases and therefore the strain increases owing to the martensitic transformation at the early stage of the unloading process. At the early stage in the reloading process, temperature increases and therefore the strain decreases owing to the reverse transformation. (3) In the case of subloop under stress-controlled conditions, the starting stresses of the martensitic transformation and the reverse transformation in the loading and unloading processes coincide with the transformation stresses under strain-controlled conditions with low strain rate, respectively. (4) The deformation behaviours for a subloop under stress-controlled conditions are prescribed by the condition for progress of the martensitic transformation based on the transformation kinetics. (5) The deformation behaviors subjected to cyclic loading under stress-controlled conditions at constant temperature are also prescribed by the conditions for progress of the martensitic transformation.
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