Numerical and experimental post-buckling analysis of slender thin-walled GLARE members subjected to compressive loading

This study deals with a post-buckling analysis of thin-walled GLARE members subjected to axial compressive loading. Considered slender and top-hat-shaped GLARE samples are made of hybrid composite that consists of alternating thin layers of aluminum alloy sheets and unidirectional glass fiberreinforced prepregs. Composite specimens were axially compressed in laboratory tests by the electromechanical static testing unit of Instron that provided a displacement control loading. Deformations were measured in full load range until specimen fracture by means of Aramis 3D noncontact optical equipment that uses the digital image correlation (DIC) method. The behavior of thinwalled GLARE members was analyzed with the primary attention to post-buckling response. Simultaneously, numerical simulations by FEM were performed to predict the load-carrying capacity of thin-walled sections. Comparative post-buckling analysis was performed based on nominal stress state in both non-degraded and degraded structure. For the latter, the damage evolution law was introduced by the material property degradation method (MPDG), which allowed a gradual reduction of material stiffness based on assumed damage variables. The impact of damage variables on the laminate loadcarrying capacity and predicted damage mode was investigated. Presented numerical results were found to be in a high agreement with experimental damage tests.