Research of effects of defects on stability failures of semi-monocoque stiffeners

    Tomáš Katrňák   Affiliation
    ; Jaroslav Juračka Affiliation
    ; Ivo Jebáček   Affiliation


This article presents further results of the research of effects of model defects on the local buckling of compressed stiffeners in nonlinear finite element (FE) analyses. The main outcomes are confirmation of trends for 10 sets of profile dimensions, final validations of various sets of FE simulations, and designs of practical types of defects with appropriate ratio values. A single node defect and then complex types of defects with alternating distributions of node shifts along one edge, two free flange edges, one flange surface and both flange surfaces are analyzed in this research project. First parts of this paper describe designed FE models with defects, their effects on simulation results, colored graphic visualizations with stress scales and determinations of the sudden failure of stability in the local mode. Then, particular results of FE analyses are validated by a comparison with the results of analytical methods of stability failure. Final detail comparisons of analytical and FE simulation results with data of experimental tests confirm predicted critical buckling forces. The validation of results and design parameters together with the knowledge of effects of model defects on buckling behaviors allows more accurate simulations of internal stiffeners of thin-walled semi-monocoque structures.

First published online 29 January 2020

Keyword : buckling, stability, failure, stress analysis, finite element methods, stiffener, imperfection

How to Cite
Katrňák, T., Juračka, J., & Jebáček, I. (2019). Research of effects of defects on stability failures of semi-monocoque stiffeners. Aviation, 23(3), 83-90.
Published in Issue
Dec 31, 2019
Abstract Views
PDF Downloads
Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.


Batista, E. de M. (2009a). Local–global buckling interaction procedures for the design of cold-formed columns: Effective width and direct method integrated approach. Thin-Walled Structures, 47, 1218–1231.

Batista, E. de M. (2009b). Stability of steel cold-formed columns and beams: Integrating effective width and direct strength methods for design. In Proceedings of the 7th EUROMECH Solid Mechanics Conference 2009 (pp. 665–668). Lisbon, Portugal.

Bruhn, E. F. (1973). Analysis and design of flight vehicle structures. Carmel: Jacobs Publishing, Carmel, USA.

Degenhardt, R., Tessmer, J., & Kling, A. (2008). Collapse behaviour of thin-walled CFRP structures due to material and geometric nonlinearities – experiments and simulation. In Proceedings of the 26th International Congress of the Aeronautical Sciences ICAS 2008 (pp. 1–10). Anchorage, Alaska, USA.

Hála, A. (2017). Stability analysis of metal stiffeners under compressive load using finite element methods (Bachelor thesis). VUT v Brně, Brno, Czech Republic (in Czech).

Hoff, N. J. (1967). Thin shells in aerospace structures. Journal of Astronautics and Aeronautics, 5(2), 26–45.

Horák, M., & Píštěk, A. (2016). Shear strength of thin web – in-fluence of lighting openings and diagonal tension. Aviation Journal, 20(1), 8–13.

Chen, T. (2014). On introducing imperfection in the non-linear analysis of buckling of thin shell structures (Master thesis). TU Delft, Delft, Netherland.

Jebáček, I., & Matějů, J. (2017). Aerobatic special in-flight tests at Institute of Aerospace Engineering. In Proceedings of the 23rd International Conference Engineering Mechanics 2017 (pp. 42–45). Svratka, Czech Republic.

Katrňák, T., & Juračka, J. (2018). Buckling analyses of compressed stiffener with finite element methods. In Proceedings of the 24th International Conference Engineering Mechanics 2018 (pp. 373–376). Svratka, Czech Republic.

Niu, M. C. Y. (1999). Airframe stress analysis and sizing: Practical design information and data on aircraft (2nd ed.). Hong Kong Conmilit Press.

Ortiz, S. S., & Martinez, A. A. (2001). Validation of post-buckling behaviour of unstable cross-section structures under compression loads. In Proceedings of the 3rd Worldwide Aero-space Conference and Technology Showcase 2002 (pp. 1–16). Toulouse, France.

Pravdová, I., & Eliášová, M. (2017). Influence of an initial imperfection on the lateral and torsional buckling of a hybrid beam. In Proceedings of the 23rd International conference Engineering Mechanics 2017 (pp. 802–805). Svratka, Czech Republic.

Soares, P. T. M. L., Monteiro, F. A. C., Neto, E. L., & Bussamra, F. L. S. (2013). Skin buckling of fuselages under compression. In Proceedings of the 22nd International Congress of Mechanical Engineering COBEM 2013.

Symonov, V., & Katrňák, T. (2013). FEM approach to estimate large deformations of stiffened fuselage structure. In Proceedings of the New Trends in Civil Aviation 2013 (pp. 90–92). Žilina, Slovak Republic.

Wang, D., & Abdalla, M. M. (2015). Global and local buckling analysis of grid-stiffened composite panels. Composite Structures, 119, 767–776.