1. Eqs. (1) and (2) suggest that the strengths and
moduli of a foam scales with r¯ 1.5 and r¯ 2, respectively,
when the tensile behaviour is dominated by
the bending of cell edges. The accumulation of
experimental evidence, as given in Fig. 3 for the
Alporas and Alcan foams, and as summarised by
Ashby et al. [10] for a wider range of metallic foams,
supports this dependence.
2. The critical tensile opening Du for which the net
section stress drops to zero in the deep notch tests is
of the order of the cell size l, rather than the
thickness of the cell faces.