Experimental and Numerical Investigation on the Failure Behaviour of Multi-Stiffener Composite Panel Under Compression

Abstract

Multi-stiffener composite panels are the primary components widely used in aircraft structures such as fuselage, wing box, and rear bulkhead, but they are typically sensitive to compressive load-induced buckling as the thin-walled nature of these components. This paper presents a numerical and experimental study on the compressive failure behaviour of multi-stiffener composite panels. A progressive damage model based on Hashin’s failure criteria was employed to model the failure behaviour of the laminates, while a cohesive zone model (CZM) was used to replicate the delamination between the stiffeners and the flat skin. The predicted initial buckling threshold and ultimate failure load agree well with the experimental data, which validated the simulation tool developed in this study. The failure mode of the MSCP was then dominated by the breakage of the stiffeners at their middle cross-section, simultaneously accompanied by delamination at the skin/stiffener interfaces. Results indicated that the initial out-of-plane buckling can cause a high level of peeling and shearing effects at the skin/stiffener interfaces, leading to skin/stiffener debonding as the compression increase. This subsequently introduced an additional bending effect to the stiffener, which eventually caused breakage in the middle stiffeners.