A Numerical Assessment of Fibre Bridging Influence on Composite Panels Skin-stringer Debonding

Numerical simulations on stiffened composite panels have been performed in order to investigate the influence of fibre bridging phenomenon on the onset and on the evolution of skin-stringer debonding. A novel numerical procedure for delamination growth simulation, implemented in ANSYS® FEM code by Ansys Parametric Design Language and enhanced to take into account GIc variations related to the fibre bridging phenomenon, has been used to numerically simulate the skin-stringer separation. Indeed, fibre-reinforced composites can develop high fibre bridging under mode I (peeling) delamination growth due to the additional resistance to crack opening offered by delaminated fibres, leading to a significant increase of mode I critical strain energy release rate. Within the present paper, a limited sensitivity analysis is presented to assess the influence of geometrical parameters of stiffened composite panels on the fibre bridging relevance in skin-stringer debonding in terms of debonded area.