Parametric Study of the Compressive Buckling Load of Composite Panels with I-shape Stiffeners

The effects of I-shape stiffeners parameters were studied on the buckling behaviors of stiffened composite panels under uniform uniaxial compressing loads. The experiments were carried out to obtain the critical buckling loads of I-shape stiffeners stiffened composite panels. A finite element model (FEM) was developed and validated by the experiments. The developed FEM was further used to study the effect of the key stiffener dimensions on the buckling loads and buckling modes of stiffened composite panels, including the width of upper and lower flange, as well as the height of the I-shape stiffeners. The analysis results showed that the width of the lower flange of I-shape stiffeners was the dominant parameter for the buckling resistance of stiffened composite panels comparing to the width of the upper flange and the height of I-shape stiffeners. The stiffened composite panels buckled locally on the skin among stiffeners with the proper design of stiffeners. Otherwise, the buckling loads of the stiffened composite panels decreased due to the global buckling of the stiffened panel when the width of the bottom edge and the height of the I-shape stiffener were excessively large. The developed FEM can be further used to optimize the geometry of I-shape stiffeners in order to obtain the maximum buckling resistance of stiffened composite panel.