An extensive literature review has been conducted in this thesis, which has shown the offset-mode turning process where the abrasive waterjet (AWJ) is applied to act on the tangential position of the workpiece, has drawbacks that limit the machining efficiency, and pointed to the need for developing a new radial mode turning process that possesses a number of advantages over the offset turning mode. In this thesis, a radial-model AWJ turning technique has been experimentally studied to understand the machining process and performance as well as the effect of processing variables, when turning an AISI 4340 high tensile steel. It is shown that the radial-mode turning with normal jet impact angle, high water pressure at high surface speed is an efficient cutting mode for high material removal rate. In order to effectively control the depth of cut in radial-mode AWJ turning, a predictive model for the depth of cut has then been developed by using the dimensional analysis technique and verified by experiment. In order to understand the impact process by individual particles in AWJ machining process, a Finite element model has been developed, considering the significant work hardening effect at high strain-rate conditions and the non-monotonic fracture locus with respect to triaxiality stress, the target thermal exchange process, and the stochastic nature of particle flow in AWJ. The model has been verified by both single and multiple particle impact experiment in AWJ. Comparisons between the model predicted and experimental data have been carried out and shown that the model predictions agreed with the experimental data. The simulation studies have shown that high strain-rate work hardening effect is a significant phenomenon in high velocity particle impact process. While crater volume is a result of overall plastic deformation, material removal is due to localized material failure, which includes the void-growth fracture mechanisms and the adiabatic shear banding, as well as the resulting chip formation. In general, sharper particles of larger sizes striking at an oblique angle with higher impact velocities, larger particle overlaps and less time interval between impacts is the most efficient condition for material removal.
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