Show simple item record

dc.contributor.advisorMahaptra, D Roy
dc.contributor.authorManna, Sukhendu Sekhar
dc.date.accessioned2018-05-25T15:11:12Z
dc.date.accessioned2018-07-31T05:14:53Z
dc.date.available2018-05-25T15:11:12Z
dc.date.available2018-07-31T05:14:53Z
dc.date.issued2018-05-25
dc.date.submitted2017
dc.identifier.urihttps://etd.iisc.ac.in/handle/2005/3624
dc.identifier.abstracthttp://etd.iisc.ac.in/static/etd/abstracts/4494/G28464-Abs.pdfen_US
dc.description.abstractThe present study in this thesis has attempted to resolve one of the key aspects of enhancing predictability of macroscopic behavior of Shape Memory Alloy (SMA) wire by considering variation of local phase inhomogeneity. Understanding of functional fatigue and its relation with the phase distribution and its passivation is the key towards tailoring thermal Shape Memory Alloy actuators’ properties and performance. Present work has been carried out in two associated areas. First part has covered solving a coupled thermo-mechanical boundary value problem where initial phase fractions are prescribed at the gauss points and subsequent evolution are tracked over the loading cycle. An incremental form of a phenomenological constitutive model has been incorporated in the modelling framework. Finite element convergence studies using both homogeneous and inhomogeneous SMA wires are performed. Effects of phase inhomogeneity are investigated for mechanical loading and thermo-electric loading. Phase inhomogeneity is simulated mainly due to process and handling quality. An example of mechanical boundary condition such as gripping indicates a negative residual strain at macroscopic behavior. Simulation accurately captures vanishing local phase inhomogeneity upon multiple cycles of thermo-mechanical loading on unconstrained straight SMA wire. In the second part, a phase identification and measurement scheme is proposed. It has been shown that by employing variation of electrical resistivity which distinctly varies with phase transformation, martensite phase volume fraction can be quantified in average sense over the length of a SMA wire. This can be easily achieved by using a simple thermo-mechanical characterization setup along with resistance measurement circuit. Local phase inhomogeneity is created in an experimental sample, which is subjected to electrical heating under constant mechanical bias load. The response shows relaxation of the initial shrinkage strain due to local phase. Results observed for thermo-electric loading on the inhomogeneous SMA wires compliment the results observed from the simulated loading cases. Several interesting features such as shrinkage of the inhomogeneous SMA wire after first loading cycle, relaxation of the residual strain over multiple loading cycles due to the presence of inhomogeneity are captured. This model promises useful applications of SMA wire in fatigue studies, SMA embedded composites and hybrid structures.en_US
dc.language.isoen_USen_US
dc.relation.ispartofseriesG28464en_US
dc.subjectInhomogeneous Phaseen_US
dc.subjectMemory Alloy Actuatorsen_US
dc.subjectPhenomenological Constitutive Modelen_US
dc.subjectShape Memory Alloy (SMA)en_US
dc.subjectActuatorsen_US
dc.subjectAdaptive Materialsen_US
dc.subjectEmbedded Compositesen_US
dc.subjectSMA Wireen_US
dc.subjectConstitutive Modellingen_US
dc.subjectSpatial Discretizationen_US
dc.subject.classificationAerospace Engineeringen_US
dc.titleA Study on the Effect of Inhomogeneous Phase of Shape Memory Alloy Wireen_US
dc.typeThesisen_US
dc.degree.nameMSc Enggen_US
dc.degree.levelMastersen_US
dc.degree.disciplineFaculty of Engineeringen_US


Files in this item

This item appears in the following Collection(s)

Show simple item record