Fig. 2. Effects of aspect ratio and geometric imperfections on the buckling direction of bi-beams.

(A) Computationally predicted maps showing the buckling direction for bi-beams with four different aspect ratios. The color code indicates the regions where right buckling occurs as a consequence of applying the corresponding nondimensional strain rate. The gray regions are the regions with conflicting results, while the orange regions highlight the occurrence of some higher modes of buckling. (B) Sensitivity of the computational results to geometric imperfections (imp.). The geometric imperfections originating from the first buckling mode (calculated using a linear buckling analysis) are applied to the geometry of bi-beams either to the left side (negative values of the buckling mode) or to the right side (positive values of the buckling mode). The predictions of buckling to the right direction are presented for different magnitudes of the applied imperfection. (C) Modification of the bi-beams design to minimize their sensitivity to geometric imperfections.