Thermomechanical constitutive modeling and numerical implementation of polycrystalline shape memory alloy materials /
A thermomechanical description of the martensitic phase transformation and the associated shape memory effect in polycrystalline shape memory alloys (SMAs) is presented. The rate-independent constitutive relations are derived in the stress- temperature space using a Lagrangian formulation. The Kuhn-...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1999.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=731681951&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | A thermomechanical description of the martensitic phase transformation and the associated shape memory effect in polycrystalline shape memory alloys (SMAs) is presented. The rate-independent constitutive relations are derived in the stress- temperature space using a Lagrangian formulation. The Kuhn-Tucker optimality conditions and constraints on the evolution of internal state variables are obtained naturally through the principle of maximum transformation dissipation. A constitutive model to capture the stress induced phase transformation is presented. Various transformation functions are investigated and a generalized transformation function is proposed. Numerical results of the model based on different transformation functions are compared with experimental results to determine their accuracy to predict SMA characteristics like tension-compression asymmetry, negative volumetric transformation strain and pressure dependence. Furthermore, a comprehensive methodology on the numerical implementation of SMA thermomechanical constitutive response using return mapping (elastic predictor-transformation corrector) algorithms has been implemented. An implicit as well as an explicit return mapping algorithm is analyzed for comparison purposes. Remarks on numerical accuracy of both algorithms are given, and it is concluded that both are applicable for this class of SMA constitutive models and preference can only be given based on the computational cost. |
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| Item Description: | Vita. "Major Subject: Aerospace Engineering". |
| Physical Description: | xvii, 185 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 157-172). |