Abstract
Aluminium extrusions have been extensively used in various industries as energy absorbing devices. Aluminium offers a series of advantages of other materials due to its unique physical characteristics. Aluminium is the most preferred metal to extrude, as it is very light in weight. Other metals like copper, brass and steel weigh as much as 3 times heavier than that of aluminium. Aluminium extrusions give very strong parts with relatively low weight. Aluminium extrusion is extremely cost effective when compared with extrusion of other metals. It produces a complete unit or small parts that can be interlocked with other metal parts to form a complete structure. Being able to figure out a method to substantially increase the energy absorption of the structure will give quality insight into its uses in the field of crashworthiness. An experimental investigation was conducted to compare the crush characteristics and energy absorption capacity of AA6061-T6 aluminium alloy extrusions with centrally two different types of throughole discontinuities. The two geometrical discontinuities were slot shaped, with Sample 1 having a slot shaped discontinuity of major axis length of 10.72mm and an aspect ratio of 2. The second sample contained the same discontinuity geometry except two additional throughole discontinuities were machined 50mm from the top and bottom respectively. The Aluminium extrusions were of length 300mm and mass 355.9 grams and 355.5 grams respectively. It was found that by introducing the crush initiators into the extrusions of 300 mm a global bending mode was observed. For the same sample of 200mm length previous studies have showed that a splitting and cutting deformation mode was generated.
Keywords: Crashworthiness, Aluminium Extrusions, Throughole discontinuities, energy absorption.