Numerical Investigation into Axial Cutting of AA6061-T6 Circular Extrusions Under Blast Loading

摘要

The study detailed in this thesis focuses on the force/time and energy absorption performances of circular AA6061-T6 aluminum alloy extrusions with the wall thickness of 3.175 mm and 1.587 mm subjected to cutting deformation modes under blast loading conditions. Numerical simulations of the detonation as well as the axial cutting deformation process employing an Eulerian finite element formulation and Smooth Particle Hydrodynamic (SPH) were performed. Numerical detonation models were in good agreement with experimental results having an average standard error less than 3% for impulse predictions. Good predictive capabilities of the numerical model employing the Eulerian element formulation for the axial cutting behaviours were observed, while the SPH formulation failed to predict experimentally observed deformation modes. The average mean cutting force, measured at the load cell for both experimental and numerical testing methods as a result of cutting deformation was observed to be 18.8 kN and 33.5 kN for the thin- and thick-walled extrusions, respectively. Force and energy analyses were conducted using theoretical and numerical models to study the steady-state cutting condition. Theoretically, it was observed that the friction force contributed 48% of total axial cutting resistant force, independent of extrusion wall thickness.