INFLUENCE OF MATERIAL UNCERTAINTY ON THE DAMAGE RESISTANCE AND TOLERANCE OF STIFFENED COMPOSITE PANELS

Composite materials exhibit complex phenomena associated with damage onset and propagation. In particular damages induced by low velocity impacts represent a main concern in aircraft structures, which may be subjected to hail impact, tools dropped during maintenance, or foreign object damage during landing and takeoff. The heterogeneous and anisotropic nature of composites allows for several modes of failure, however it has been observed that the most dangerous and unpredictable one is the delamination, which can considerably reduce the inplane compressive strength of the laminates. The development of damage resistance and damage tolerance design methodologies have allowed a more efficient management of the damage in composites. However these methodologies strongly depend on composite material properties, which are affected by an intrinsic uncertainty. In this paper the effect of the material properties scatter on the damage resistance and the damage tolerance of composites will be assessed by using a probabilistic approach.