This paper describes the laboratory experiments conducted on specimens with
artificially created internal structure produced by drilling a regular pattern
of circular holes in an alumnium matrix. The specimens are subjected to
four-point bending and the protocol is described in detail with emphasis given
on the top-edge and bottom-edge axial-strain measurement and processing
in the zone of pure bending. An increase in stiffness is observed with the
reduction in the characteristic specimen dimension (size effect), which may be
explained by the micropolar theory of elasticity. A methodology is suggested
for establishment of the effective Young’s modulus and the characteristic
bending length of a homogenised substitute micropolar material, which is
entirely based on a known closed-form pure-bending solution. The results
are compared with those obtained using an alternative protocol from the
literature.
Keywords
pure bending, four-point bending, architected internal
structure, homogenisation, micropolar theory