Modeling of the thermomechanical behavior of porous shape memory alloys

Qidwai, Muhammad A.; Entchev, Pavlin B.; Lagoudas, Dimitris C.; DeGiorgi, Virginia G.

doi:10.1016/s0020-7683(01)00118-4

Cited by 88 publications

(61 citation statements)

References 42 publications

(39 reference statements)

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“…Efforts to model the effective thermomechanical response of porous SMAs have been made by Lagoudas et al (2001), Qidwai et al (2001), and Entchev and Lagoudas (2001). In these works the mechanical quasi-static behavior of porous NiTi was modeled using a micromechanics averaging model and Unit Cell Finite Element Method (UCFEM).…”

Section: Pseudoelastic Testing Of Porous Niti Under Uniaxial Quasi-stmentioning

confidence: 99%

Processing and Characterization of NiTi Porous SMA by Elevated Pressure Sintering

Lagoudas

Vandygriff

2002

Journal of Intelligent Material Systems and Structures

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Currently, three methods are commonly used for producing porous NiTi shape memory alloys (SMAs) from elemental powders. These include conventional sintering, Self-propagating High temperature Synthesis (SHS), and sintering at elevated pressure via a Hot Isostatic Press (HIP). Conventional sintering requires long heating times and samples are limited in shape and pore size. SHS is initiated by a thermal explosion ignited at one end of the specimen, which then propagates through the specimen in a self-sustaining manner. One of the difficulties with SHS is the inability to control intermetallic phases. This work will focus on the fabrication and characterization of porous NiTi SMA material produced from elemental powders via HIPping.Porous NiTi SMA was produced from elemental Ni and Ti powders at elevated temperature and pressure using a Hot Isostatic Press (HIP). Small and large pore specimens containing average pore sizes ranging from 20 microns up to 1mm have been produced by slightly varying the HIPping sintering temperatures and times.Quasi-static and dynamic loading experiments are conducted on various samples produced using the presented methodology and their shape recovery and energy absorption characteristics are measured during the forward and reverse phase transformation and detwinning. Their phase transformation characteristics were found using calorimetric measurements and their composition has been studied using optical and electron microscopy and microprobe x-ray analysis.

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Section: Pseudoelastic Testing Of Porous Niti Under Uniaxial Quasi-stmentioning

confidence: 99%

Processing and Characterization of NiTi Porous SMA by Elevated Pressure Sintering

Lagoudas

Vandygriff

2002

Journal of Intelligent Material Systems and Structures

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“…Due to the periodicity and symmetry exhibited by this foam, there is no need to reproduce a complete foam structure, since only a small part of it is needed to capture the macroscale behaviour of the foam, provided that the specific boundary conditions are applied (addressed in the next section). This approach, the so-called Unit Cell Finite Element Method (UCFEM), has already been widely used [27,28] and makes it possible to circumvent the huge numerical weight exhibited by a full foam model.…”

Section: Geometrical Aspectsmentioning

confidence: 99%

Unit Cell Analysis of the Superelastic Behavior of Open-Cell Tetrakaidecahedral Shape Memory Alloy Foam under Quasi-Static Loading

Maîtrejean

Terriault

Capilla

et al. 2014

Smart Materials Research

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properly cited.Cellular solid materials and, more specifically, foams are increasingly common in many industrial applications due to their attractive characteristics. The tetrakaidecahedral foam microstructure, which can be observed in many types of foams, is studied in the present work in association with shape memory alloys (SMA) material. SMA foams are of particular interest as they associate both the shape memory effect and the superelasticity with the characteristics of foam. A Unit Cell Finite Element Method approach is used, an approach that allows accurate predicting of the macroscale response of the foam with a highly reduced numerical effort. The tetrakaidecahedral foam's responses, both in the elastic and in the superelastic stages, are then extracted and compared with results from the literature. The tetrakaidecahedral geometry is found to be of particular interest when associated with SMA as it takes more advantage of the superelastic property of the material than foams with randomly distributed porosity.

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“…As suggested in [18,9], for rectangular 2D unit cells with the total dimensions along the two coordinate axes 1 x , 2 x denoted by 1 2a and 2 2a , the classical periodicity conditions:…”

Section: Periodic Microstructurementioning

confidence: 99%

“…The porous SMA material can be treated as a composite with SMA as the matrix and pores as the inclusions. In order to derive the mechanical response of porous SMA, micromechanical averaging techniques have been developed in the available literature, as for instance [9,10]. Indeed, different micromechanical and homogenization techniques, usually applied to study composites can be used to model porous SMA, such as the Eshelby dilute inclusion technique or the Mori-Tanaka scheme [11,12] or the selfconsistent method.…”

Section: Introductionmentioning

confidence: 99%

Response of porous SMA: a micromechanical study

Sepe

Marfia

Auricchio

2014

Frattura Ed Integrità Strutturale

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ABSTRACT. Lately porous shape memory alloys (SMA) have attracted great interest as low weight materials characterized by high energy dissipation capability. In the present contribution a micromechanical study of porous SMA is proposed, introducing the simplifying hypothesis of periodic distribution of voids. The mechanical response of the heterogeneous porous medium is derived by performing nonlinear finite element micromechanical analyses considering a typical repetitive unit cell made of a circular hole in a dense SMA matrix and prescribing suitable periodicity and continuity conditions. The constitutive behavior and the dissipation energy capability of the porous Nitinol are examined for several porosity levels. Numerical applications are performed in order to test the ability of the proposed procedure to well capture the overall behavior and the key features of the special heterogeneous material.

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Modeling of the thermomechanical behavior of porous shape memory alloys

Cited by 88 publications

References 42 publications

Processing and Characterization of NiTi Porous SMA by Elevated Pressure Sintering

Processing and Characterization of NiTi Porous SMA by Elevated Pressure Sintering

Unit Cell Analysis of the Superelastic Behavior of Open-Cell Tetrakaidecahedral Shape Memory Alloy Foam under Quasi-Static Loading

Response of porous SMA: a micromechanical study

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