The Influence of Thermal Conditions on the Stability and Load-Carrying Capacity of Compressed Thin-Walled Composite Profiles

This paper presents experimental and numerical investigations on thin-walled carbon-epoxy composite structures subjected to axial compression under varying thermal conditions. The primary objective of the study was to determine the influence of temperature on the stability, postbuckling behavior, and load-carrying capacity of the tested profiles. To achieve this, an innovative research methodology combining laboratory experiments and numerical simulations was developed, enabling a comprehensive assessment of the performance of compressed composite structures at different operating temperatures. The obtained results allowed for both qualitative and quantitative evaluation of the temperature-dependent behavior (from -20 °C to +80 °C) of thin-walled composite elements under compressive loading, offering new insights into their structural performance in thermally variable environments. The maximum percentage change in load capacity under variable thermal conditions was approximately 26.5%. At sub-zero temperatures (-20 °C), a slight effect on the load-carrying capacity of composite structures was observed, with a change in stiffness of a few percent. At increased above-zero temperatures (+80 °C), a significant change in stiffness (up to several dozen percent) was observed. The strengths of the work are a relatively extensive experimental program across several temperatures and stacking sequence composites, the use of digital image correlation to capture buckling and postbuckling deformations, and the parallel use of numerical modeling.