This dissertation addresses new developments in the constitutive modeling and
structural analysis pertaining to rate-independent and rate-dependent irrecoverable
inelasticity in Shape Memory Alloys (SMAs). A new model for fully recoverable SMA
response is derived that accounts for material behaviors not previously addressed.
Rate-independent and rate-dependent irrecoverable deformations (plasticity and viscoplasticity)
are then considered. The three phenomenological models are based on
continuum thermodynamics where the free energy potentials, evolution equations, and
hardening functions are properly chosen. The simultaneous transformation-plastic
model considers rate-independent irrecoverable strain generation and uses isotropic
and kinematic plastic hardening to capture the interactions between irrecoverable
plastic strain and recoverable transformation strain. The combination of theory and
implementation is unique in its ability to capture the simultaneous evolution of recoverable
transformation strains and irrecoverable plastic strains. The simultaneous
transformation-viscoplastic model considers rate-dependent irrecoverable strain generation
where the theoretical framework is modfii ed such that the evolution of the
viscoplastic strain components are given explicitly. The numerical integration of the
constitutive equations is formulated such that objectivity is maintained for SMA
structures undergoing moderate strains and large displacements. Experimentally validated
analysis results are provided for the fully recoverable model, the simultaneous
transformation-plastic yield model, and the transformation-viscoplastic creep model.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2009-12-7573 |
| Date | 2009 December 1900 |
| Creators | Hartl, Darren J. |
| Contributors | Lagoudas, Dimitris C. |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | application/pdf |
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