Evolution of energy dissipation mechanisms over a comprehensive range of cutting modes and enhanced capabilities via hybrid cutting/clamping in AA6061 extrusions

摘要

Safety system design requires an in-depth understanding of the fundamental mechanisms responsible for energy absorption in a given deformation mode, which often necessitates substantial experimental evidence to support the development of theory. A comprehensive study of axial cutting with a broad range of cutting tools was conducted for AA6061 extrusions in T6 and T4 temper conditions with several diameters and wall thicknesses. Assessing key aspects of the observed deformation modes, and how they evolved with increasing blades was of particular interest. The consequences of this exercise were significant, revealing details on phenomena which were not explored in the existing literature and hence were rigidly defined for the first time in the present study. A trend of force attenuation was the most critical observation, with the cutting force per blade observed to decrease by approximately 36% from 4 to 10-bladed cutting. The total force consistently increased, although not proportionately due to this trend of diminishing returns. Additionally, a localized peak force was observed to occur as the extrusion initially cleared the shoulder of the blades which became more pronounced as the number of blades was increased. A hybrid cutting/clamping deformation mode was demonstrated as an effective option for further energy dissipation by increasing the steady-state force by approximately 25% for the 10-bladed cutting mode. An enhanced analytical modeling procedure was derived which considered the transient loading, steady-state force attenuation, evolving peak wedge force and hybrid cutting/clamping. Average validation metrics and cumulative errors of 0.934 and 0.066 were calculated, respectively.