Residual Strength of an ARALL Laminate Containing a Crack

The residual tensile strength of a cracked ARALL (ARamid-fibre-reinforced-polymer/ALuminium Laminates) sandwich with an aramid-fibre/epoxy ply in the middle and two aluminium alloy plies on the outside is studied in this paper. It is assumed that both a Dugdale strip yielding zone in the aluminium layers and a strip damage zone in the fibre composite layer are developed concurrently at the crack tip. Two important parameters have been identified and these are the maximum separation displacement δ ₀ of the fibre composite damage zone and the metal deformation parameter J _c /σ _ys where J _c is the critical J-integral and σ _ys is the yielding strength of the metal. The requirement that the strength of ARALL is comparable to that of their metal counterpart can be met if δ0 is close to J _c /σ _ys