Friday, October 24, at 2:00 pm, Selçuk Hazar, doctorant at UME, will present his thesis "Theoretical and Numerical Analysis of Fracture of Shape Memory Alloys".
Summary of the thesis :
The subject of this thesis is theoretical and numerical analysis of the fracture of SMAs. For this purpose first, the size of the martensitic region surrounding the tip of an edge-crack in a SMA plate is calculated analytically using the transformation function proposed by Zaki and Moumni (Zaki and Moumni, J. Mech. Phys. Sol, 2007) Transformation regions calculated analytically and computationally are compared to experimental results available in the literature (Robertson et al., Acta Mater., 2007). Second, fracture parameters are evaluated. The objective at this point is to understand the effect of phase transformation on fracture behavior of an edge-cracked Nitinol plate under Mode I loading. Third, steady-state crack growth in an SMA plate is analysed. To this end, Mode I steady-state crack growth in an edge-cracked Nitinol plate is modeled using a non-local stationary method to implement the Zaki-Moumni model in Abaqus. Finally, phase transformation regions are calculated analytically around the tip of an SMA specimen under Mode III loading. The model proposed by Moumni is subsequently improved by including latent heat generation through thermomechanical coupling. The influence of coupling on the size of the phase transformation regions and on temperature distribution within the material is then investigated numerically.