Zirconium is a widely applied material in nuclear industry and characterized by highly anisotropic mechanical behaviour. With the development of the nuclear industry, zirconium alloys have proven to be very important structural material used as pressure tubes in heavy water reactors, and thin-walled tubing in light water reactors due to improved corrosion resistance. To study the special property of zirconium, this thesis will evaluate different numerical models and will present an overview about the deformation mechanisms for zirconium alloys. Twinning and De-twinning (TDT) and Predominant Twin Reorientation (PTR) models are both implemented in the EVPSC polycrystal model. Various self-consistent models as well as TDT and PTR twinning models are evaluated by studying large strain behavior of zirconium alloys slab under different deformation processes. The material parameters for those models are determined by virtue of the experimental uniaxial tension and compression along the normal direction (ND) as well as tension along the rolling direction (RD). The predictability of those models is assumed through comparison of macroscopic deformation behavior (stress strain curves and R values) and microscopic mechanical response (texture coefficients and lattice strain) between the predicted and experimental data. Numerical results reveal that, among the various models examined, the VPSC-TDT model with the Affine self-consistent scheme gives the best overall performance for zirconium alloys slab, TDT twinning model gives the better overall performance than the PTR twinning model. / Thesis / Master of Applied Science (MASc)

High hydrodynamic pressure (HDP) treatment is a novel non-thermal technology that improves tenderness in foods by subjecting foods to underwater shock waves. In this study non-destructive and destructive testing methods, along with two mathematical models were explored to predict biomechanical behavior of beef loins subjected to HDP-treament. The first study involved utilizing ultrasound and imaging techniques to predict textural changes in beef loins subjected to HDP-treatment using Warner-Braztler shear force (WBS) scores and texture profile analysis (TPA) features for correlation. Ultrasound velocity correlated very poorly with the WBS scores and TPA features, whereas the imaging features correlated better with higher r-values. The effect of HDP-treatment variables on WBS and TPA features indicated that amount of charge had no significant effects when compared to location of sample and container size during treatment. Two mathematical models were used to simulate deformational behavior in beef loins. The first study used a rheological based modeling of protein gel as a preliminary study. Results from the first modeling study indicated no viscous interactions in the model and complete deformation failure at pressures exceeding 50 kPa, which was contrary to the real-life process conditions which use pressures in the order of MPa. The second modeling study used a finite element method approach to model elastic behavior. Shock wave was modeled as a non-linear and linear propagating wave. The non-linear model indicated no deformation response, whereas the linear model indicated realistic deformation response assuming transverse isotropy of the model beef loin. The last study correlated small- and large-strain measurements using stress relaxation and elastic coefficients of the stiffness matrix as small-strain measures and results of the study indicated very high correlation between elastic coefficients c11, c22, and c44 with TPA cohesiveness (r > 0.9), and springiness (r > 0.85). Overall results of this study indicated a need for further research in estimating mechanical properties of beef loins in order to understand the dynamics of HDP-treatment process better. / Ph. D.