A Study on Skin Delaminations Growth in Stiffened Composite Panels by a Novel Numerical Approach

In this paper, a study on skin delamination growth in stiffened composite panels made of carbon fibres reinforced polymers and subjected to compressive load is presented. A robust (mesh and time step independent) numerical finite elements procedure, based on the Virtual Crack Closure Technique (VCCT) and on the fail release approach, is used here to investigate the influence of skin delamination size and position on the damage tolerance of stiffened composite panels. Four stiffened panels configurations with skin delaminations differently sized and positioned are introduced. Bay delaminations and delaminations under the stringer foot are considered. The novel numerical procedure has been used to simulate the delamination growth for all the investigated panel configurations and to evaluate the influence of the delaminations' geometrical parameters on the growth development. As a confirmation of the applicability and effectiveness of the adopted numerical tool, the numerical results, obtained for all the analysed configurations, in terms of grown delaminated area, displacements and strains measured in various panel locations, have been compared with experimental data available in literature.