Buckling of Compressed Thin-Walled Composite Structures with Closed Sections

The purpose of the study was to conduct an experimental-numerical analysis of the critical state (buckling) of thin-walled composite structures with a square cross-section. The subject of the study was thin-walled composite structures, which were made of CFRP - carbon epoxy composite. The structures were characterized by a closed square cross-sectional shape. In the research paper, stability tests of axially compressed thin-walled struts were performed in order to determine the critical state of the structures. Experimental tests were carried out on a universal testing machine, using a system for optical measurement of deformation of structures. Numerical simulations were carried out using the finite element method (FEM). The research made it possible to evaluate the work of the structure in the buckling state from a qualitative as well as quantitative point of view. During the study, the buckling form and the corresponding critical load were determined - which quantitatively and qualitatively showed high agreement for both experimental testing and numerical simulation. The novelty of the present paper was the use of several interdisciplinary research methods (testing machine, optical deformation measurement system and numerical simulations) in order to determine the critical state of thin-walled composite structures with closed sections.