Buckling behavior of curved composite beams with different elastic response in tension and compression

A geometrically nonlinear finite element model of a composite curved beam is presented, accounting for moderately large rotations of the cross-sections, moderately large shear strains, small axial strains, and different elastic response of the material in tension and compression (bimodular behavior). A path following procedure in displacement control is employed to compute the stability points and the post-buckling response of the given model. Several comparisons are established with different numerical approaches available in the literature, showing the accuracy of the proposed finite element scheme in the unimodular case. Some original results on the in-plane and out-of-plane buckling of bimodular arches highlight that the post-buckling response of such structures is strongly influenced by the ratios between tensile and compressive moduli.