Progressive delamination with and without crack propagation in aramid fiber reinforced metal laminates containing a circular notch

If aramid fiber reinforced metal laminates (AFRMLs) were delaminated, the decrease of stiffness and fiber bridging effect would result in the sudden aggravation of fatigue characteristics. It was reported that the delamination of AFRMLs resulted from cracking Al alloy layers and that it depended on the crack propagation. When AFRMLs with circular holes were not cracked but were delaminated, it was impossible to analyze them by conventional fracture parameters expressed as a function of crack size. Therefore, a new analytical model called pseudo-crack model (PCM) was suggested to compare the delamination, whether cracked or not. The relationship between the crack consumption rate (Ccrack) and the delamination consumption rate (Cdel) was discussed. The effect of the Ccrack was larger than that of the Cdel.