Background: Advanced lightweight laminated composite shells are increasingly being used in modern aerospace structures to enhance their structural efficiency and performance. Such thin-walled structures are susceptible to buckling when subjected to static and dynamic compressive stresses. This paper reports on the numerical (finite element method (FEM)) study on buckling of carbon fibre-reinforced plastic (CFRP) layered composite cylinders under displacement and load-controlled static axial compression. Methods: The effects of geometric properties, lamina lay-up, amplitudes of imperfection and parametric research of the shape (square, circular) and the dimensions (axial and circumferential sizes, diameter) of the opening on the strength of the cylinders under compression were studied. The measurement of imperfections on the cylindrical surface is achieved using the interpolation method and Fourier series. Results: The analysis indicates that the critical load is sensitive to the circumferential size of the opening. The function (critical load-circumferential size of the opening) is linear for large openings and independent of the geometrical imperfections of the shell. However, for small openings, it is necessary to take into account the coupling between the initial geometrical imperfections and the openings. Conclusions: The linear approach does not fit due to the importance of the evolution of the displacements near the openings. Also, it was shown that the buckling behaviour of thin composite cylindrical shells can be evaluated accurately via modelling to determine the imperfections and the material properties in FEM.
