Investigation on strength loss in buckling of composite columns subjected to fatigue loading

In current research, the loss in buckling strength of a composite column has been calculated at various phases of its total fatigue cycles, and a comparison between damaged and undamaged columns has been made. The calculation scheme is built upon a progressive methodology and verified according to the experimental outputs of previous research available in the literature. The buckling loads have been computed numerically for composite columns subjected to partial fatigue loadings corresponding to certain predefined percentages of their total fatigue life. Two axial load magnitudes were used in the fatigue process. Several types of geometric cutouts were considered, as well as the sample with no cutout. It was found that cutouts introduced to the column samples significantly affect the buckling strength of partially fatigued samples. The samples with no cutout can preserve buckling strength for up to 40% of the total fatigue life without undergoing any substantial loss. For the higher fatigue load case, especially for the samples with elliptic and circular cutouts, the buckling strength loss is relatively smaller as compared to the lower fatigue load case (around 50 to 66%). The results were presented and interpreted.