Micromechanical modeling of porous shape memory alloys /
A thermomechanical constitutive model for fully dense shape memory alloys (SMAs) is developed in this work. The model accounts for development of transformation and plastic strains during martensitic phase transformation, as well as for the evolution of the transformation cycle. The developed model...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
2002.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=726464341&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A thermomechanical constitutive model for fully dense shape memory alloys (SMAs) is developed in this work. The model accounts for development of transformation and plastic strains during martensitic phase transformation, as well as for the evolution of the transformation cycle. The developed model is used in a micromechanical averaging scheme to establish a micromechanics-based model for the macroscopic mechanical behavior of porous shape memory alloys. The derivation of the micromechanical model is presented for the general case of a composite with phases undergoing rate-independent inelastic deformations. Micromechanical averaging techniques are used to establish the effective elastic and inelastic behavior based on information about the mechanical response of the individual phases and shape and volume fraction of the inhomogeneities. An explicit expression for the effective tangent stiffness and an evolution equation for the effective inelastic strain are derived. A detailed study on the choice of the pore shape is performed for a random distribution of pores. The material parameters used by the model are estimated for the case of porous NiTi SMA processed from elemental powders and the results of the model simulations are compared with the experimental data. The numerical implementation of the model is also presented in this work. Various loading cases for porous SMA bars have been simulated using the implementation of the model. |
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| Item Description: | Vita. "Major Subject: Aerospace Engineering". |
| Physical Description: | xiv, 192 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 177-191). |