A model for memory alloys in plane strain

Achenbach, M.; Atanacković, Teodor M.; Müller, Ingo

doi:10.1016/0020-7683(86)90006-5

Cited by 44 publications

(13 citation statements)

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“…The MAS model rationalizes this observation by considering ideal mesoscopic crystal layers in one of the three model phases austenite (A) and two martensitic twin phases (M+, MÀ) (Ref [3][4][5][6][7][8][9][10][11]. The model derivation adheres strictly to thermodynamics and roots in the idea of a three-well potential energy with minima indicating the stable locations of these three phases.…”

Section: The Mas Model and Its Fem Implementation In Generalmentioning

confidence: 96%

Finite-Element Simulation of the Anti-Buckling-Effect of a Shape Memory Alloy Bar

Richter

Kastner

Eggeler

2011

J. of Materi Eng and Perform

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Shape memory alloys (SMA) are characterized by an intricate stress-strain curve modified by temperature, posing thermomechanically coupled problems. A model able to address this feature is the Mü ller-Achenbach-Seelecke (MAS) model which had been ported into the user material interface in the finite-element (FEM) simulation software ABAQUS. The literature on this model mainly focuses on pseudo-elasticity of SMA at elevated temperature. We address a numerical investigation in the low-temperature pseudo-plastic regime. The present publication deals with the little-known anti-buckling effect which occurs in de-twinned and pre-bent martensitic bars under axial compression. It was experimentally demonstrated by Urushiyama et al. (JSME (The Japan Society of Mechanical Engineers) Int. J. Ser. A, Solid Mech. Mater. Eng., 2003, 46(1), p 60-67). This study reveals that the origin of this effect roots in an interplay of inhomogeneous stress states and mechanically induced twin-twin phase transformations. The proper explanation of the anti-buckling effect can be inferred from the explicit knowledge of the martensitic phase composition of the bar during the process. We show that the MAS model is capable to resolve this matter in detail, hence addressing the reliability of this particular model also in the pseudo-plastic regime of SMA. The study thereby implies that the MAS model is an excellent modeling tool for the analysis of complex, thermomechanically coupled processes.

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Section: The Mas Model and Its Fem Implementation In Generalmentioning

confidence: 96%

Finite-Element Simulation of the Anti-Buckling-Effect of a Shape Memory Alloy Bar

Richter

Kastner

Eggeler

2011

J. of Materi Eng and Perform

View full text Add to dashboard Cite

show abstract

“…E1I denotes the bending rigidity of the instrument; R2 and R4 are characteristic radii of curvature; and E1 and E2 are moduli of elasticity corresponding to the primal and secondary elastic paths. As stated by Achenbach et al 6) , the formula showed an important factor in the bending of Ni-Ti rods: the layers subjected to maximum stress need not be the outer ones. In other words, maximum stress in an inner layer might produce voids which are not visible, hence leading to a sudden and unexpected fracture of the instrument.…”

Section: Mathematical Modelmentioning

confidence: 90%

“…However, it does not return along the same path in the σ-ε plane, exhibiting the pseudoelastic hysteresis effect shown in Fig. 3 6,7,9,14) . Further, the rotary Ni-Ti instrument functions as a rotating rod.…”

Section: Mathematical Modelmentioning

confidence: 95%

“…On the basis of this observation, we modifi ed the Coffi n-Manson relation 8) . Nickel-titanium alloy is a pseudoelastic material 6,7,13,14) . It deforms with the application of forces and torques and returns to the original shape after the forces and torques are removed (elastic property).…”

Section: Mathematical Modelmentioning

confidence: 99%

“…Therefore, the purpose of this study was to examine the lifespan of rotary Ni-Ti endodontic instruments via simulated root canals with different curvatures. By connecting experimental data to relations formulated by Achenbach et al 6) , Atanackovic and Achenbach 7) , Meyers and Kumar 8) and Zbiciak 9) to simulate the pseudoplastic behaviour of Ni-Ti shape memory alloys when under cyclic loading, a novel mathematical model was derived which could be used to predict the bending fatigue life of rotary Ni-Ti endodontic instruments.…”

Section: Introductionmentioning

confidence: 99%

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Predicting in vivo failure of rotary nickel-titanium endodontic instruments under cyclic fatigue

et al. 2012

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The aim of this study was to examine the lifespan or number of cycles to failure of tapered rotary nickel-titanium (Ni-Ti) endodontic instruments. Simulated root canals with different curvatures were used to determine a relation between canal curvature and instrument lifespan. Using a novel mathematical model for the deformation of pseudoelastic Ni-Ti alloy, it was shown that maximum stress need not necessarily occur at the outer layer. On the basis of this observation, the Coffi n-Manson relation was modifi ed with parameters determined from this experiment. Results showed that the number of cycles to failure was infl uenced by the angle and radius of canal curvature and the size of instrument at the beginning of canal curvature. The resulting quantitative mathematical relation could be used to predict the lifespan of rotary Ni-Ti endodontic instruments under clinical conditions and thereby reduce the incidence of instrument failure in vivo.

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Special metals for seismic retrofitting of steel buildings

Sarno

Elnashai

2003

Progress Structural Eng Maths

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Novel metals such as aluminium alloys, stainless steels and shape memory alloys can be used for the retrofitting of steel buildings in seismic areas. Therefore, it is useful to investigate their mechanical and physical properties along with the key issues of the material modelling. The present paper focuses on the mechanical response of such metals which are inherent to the seismic design. Furthermore, it compares their mechanical characteristics in order to assess (i) the relative merits; and (ii) the cost‐effectiveness in practical applications. Analytical formulations employed for either refined or simplified modelling are critically reviewed; advantages and disadvantages of each scheme are highlighted. Finally, several examples of practical applications of these novel metals in seismic retrofitting are discussed and further developments outlined. Copyright © 2003 John Wiley & Sons, Ltd.

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A model for memory alloys in plane strain

Cited by 44 publications

References 1 publication

Finite-Element Simulation of the Anti-Buckling-Effect of a Shape Memory Alloy Bar

Finite-Element Simulation of the Anti-Buckling-Effect of a Shape Memory Alloy Bar

Predicting in vivo failure of rotary nickel-titanium endodontic instruments under cyclic fatigue

Special metals for seismic retrofitting of steel buildings

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