cross section crash boxes

In automobiles, the use Al foams improves the crash safety by increasing the energy
absorbing capacity of crash boxes and the stiffness of specific areas of A/B pillars and
by supporting the rail on chassis. They are also prominent materials, as being very light,
for the space applications. An example of space applications, Ariene 5 rocket cone Al
foam structure, was shown by Scwingel et al.(Schwingel, et al.). The mechanical
properties of Al closed-cell foam have been extensively studied including uniaxial
stress-strain response (McCullough, et al. 1999b), strain rate sensitivity (Hall, et al.
2000), energy absorption (Song and Nutt 2005), drop weight impact (Rajendran, et al.
2009a), fracture toughness (McCullough, et al. 1999a) and internal reinforcing with
steel netting (Solorzano, et al. 2007).
2.2. Processing of Al Closed Cell Foams
A cellular solid is one made up of an interconnected network of solid struts or
plates which form the edges and faces of cell(Gibson and Ashby 1997). In this
definition, strut stands for the cell edge and plate for the cell face. Note that, an open
cell foam is solely made of struts (Figure 2.2(a)) and a closed-cell foam is made of
struts and plates (Figure 2.2(b)). As noted in Figures 2.2 (b), the cell faces are thinner
than cell edges.
(a) (b)
Figure 2. 2. Schematic representation of a) an open and b) an closed cell cellular
structure (Source :Gibson and Ashby 1997).
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