STABILITY AND POST-BUCKLING BEHAVIOR OF FIBER COMPOSITE PANELS UNDER AXIAL COMPRESSION
DOI:
https://doi.org/10.35546/kntu2078-4481.2026.2.23Keywords:
composite buckling; CFRP; GFRP; finite element analysis; mesh convergence; buckling mode visualisation; thin-walled aerospace structuresAbstract
This study examines the compressive buckling behaviour of cylindrical shell panels fabricated from carbon fibrereinforced
polymer (CFRP) and glass fibre-reinforced polymer (GFRP) through finite element (FE) analysis. Emphasis is
placed on how elastic anisotropy, mesh density, and buckling mode geometry affect the reliability and practical utility of
numerical predictions. With a longitudinal modulus of 135 GPa, CFRP exceeds GFRP (42 GPa) by a ratio greater than
three, and this disparity in bending stiffness governs the critical load at which a panel transitions from stable compression
to instability. A systematic mesh refinement study performed on the representative CFRP-S1 cylindrical shell (radius R =
150 mm, length L = 500 mm, wall thickness t = 2 mm) confirms numerical convergence at 16 000 elements: the predicted
critical load reaches 59.4 kN, and further refinement alters this value by no more than 0.2%. Three-dimensional renderings
of the first and second buckling modes – defined by n = 5, m = 3 and n = 6, m = 4 half-waves respectively – expose
the spatial character of composite instability in a format that directly supports structural design decisions. The work
delivers a validated, self-contained FE workflow together with a transparent quantitative framework for guiding material
selection and panel dimensioning during the conceptual phase of composite airframe design. Boundary conditions were
enforced as fully clamped at the loaded edge with a uniform axial displacement applied at the opposite end, replicating
the constraint state typical of frame-to-skin attachment zones in fuselage construction. Post-buckling response was
characterised by tracking the load-shortening relationship beyond the bifurcation point, revealing that CFRP panels
retain a measurable post-critical load-carrying capacity whereas GFRP panels exhibit a more abrupt loss of stiffness.
These findings underscore the importance of accounting for post-buckling reserve in weight-optimised composite designs
and demonstrate that the proposed FE methodology provides the quantitative fidelity required for certification-level
analysis of thin-walled aerospace panels.
References
Reddy, J. N. (2003). Mechanics of Laminated Composite Plates and Shells: Theory and Analysis (2nd ed.). CRC Press.
Kaw, A. K. (2006). Mechanics of Composite Materials (2nd ed.). CRC Press.
Vinson, J. R., & Sierakowski, R. L. (2008). The Behavior of Structures Composed of Composite Materials (2nd ed.). Springer.
Hyer, M. W. (1998). Stress Analysis of Fiber-Reinforced Composite Materials. McGraw-Hill.
Daniel, I. M., & Ishai, O. (2006). Engineering Mechanics of Composite Materials (2nd ed.). Oxford University Press.
Tsai, S. W., & Hahn, H. T. (1980). Introduction to Composite Materials. Technomic.
Kollár, L. P., & Springer, G. S. (2003). Mechanics of Composite Structures. Cambridge University Press.
Srinivasan, A. V., Graesser, D. L., & Loewy, R. G. (1986). Buckling of composite plates: Theory and experiment. AIAA Journal, 24(3), 458–464.
Chandrashekhara, K., & Kim, T. H. (1993). Buckling analysis of composite panels incorporating higher-order shear deformation. Composite Structures, 25(1), 1–10.
Vasiliev, V. V., & Morozov, E. V. (2007). Advanced Mechanics of Composite Materials (2nd ed.). Elsevier
