We explore a novel cellular topology structure based upon assemblies of square cross
section tubes oriented in a cross-ply 2D and orthogonal 3D arrangements that can be
tailored to support different combinations of through thickness and in-plane loads.
A simple dip brazing approach is used to fabricate these structures from
assemblies of extruded 6061-T6 aluminum alloy tubes and the through thickness
compression of a variety of structures is investigated experimentally and with
finite element modeling. We find that the 3D orthogonal structures have an
approximately linear dependence of modulus upon relative density. However the
strength has a power law dependence upon density with an exponent of
approximately 5/3. These cellular structures exhibit almost ideal plastic energy
absorption at pressures that can be selected by adjustment of the vertical
and in-plane tube wall thicknesses. A finite element model with a nonlinear
hardening constitutive law is used to explore the buckling modes of the
structure, and to investigate the relationship between cell topology, relative
density, tube wall material properties and the cellular structures resistance to
compression.
Keywords
cellular structures, 6061 aluminum, impact energy
absorption