Project start: 1.10.2025.

Since contemporary composite load-carrying structures usually contain slender thin-walled beam structural elements, the response of such weight-optimized structures to the action of external loads is at the same time much more complex, and their increased tendency to instability of deformation forms is particularly pronounced. Instability of beam members could occur in a pure flexural, pure torsional, torsional-flexural or lateral-torsional deformation form, respectively. In the case of thin-walled beam members, a local form of instability can also occur, which further reduces the stability strength of the structure.

The great potential of laminate, FRP and FG composites causes the frequent replacement of conventional materials in engineering applications, primary in aerospace industry and in past few decades also in civil engineering applications, due to the various advantages, primarily their durability, lightness and corrosion resistance, wherever is possible and cost-effective. Thus, in the optimal structural design an important consideration should concern the accurate prediction of the stability limit state of pertaining deformation forms.

To address these challenges, researchers have introduced geometric nonlinear analyses of composite beam structures considering large rotation effects, cross-sectional warping and shear deformation effects, respectively, thermal effects, as well as bending-torsion coupling effects occurring when the principal bending and shear axes of a cross-section do not coincide, or due to the nonsymmetric and unbalanced stacking sequence at laminates.

The research that will be conducted within this project will include further development of existing proprietary finite element algorithms for modeling the geometrically nonlinear response of composite beam and frame structures, frame structures with semi-rigid connections, and problems of the influence of shear deformability of the cross-section on structural stability.