SS-V: 5020 Lateral Buckling of a Right Angle Frame

Definition

Perform analysis of buckling and post-buckling of a thin-walled frame-like structure in the shape of right angle (Figure 1). One end of the structure is clamped, and a conservative load in X-directions is applied to the other end.

The material properties are:

Properties

Value

Modulus of Elasticity

7.124e+10 pa

Poisson's Ratio

0.31

Results

Structure is simulated as a solid. Reference critical load found from 1D beam bending model of the structure is P = 0.820035 N. Negligible perturbation load of Pz = P*1.e-4 = 8.2e-5 N is applied in lateral Z-direction at the loaded end of the structure in order to cause a very small initial deflection of the structure from the flat. The main load was gradually increased from 0 to 1.6*P.

Figure 2 shows maximum deflections versus applied load. The load-lateral deflection curve is in a good agreement with the results reported in the reference. Transversal post-buckling behavior at first is associated with a very small transversal stiffness, but then the load carrying capacity increases (load-displacement curve flattens). In-plane behavior is almost monotonic, no capacity increase occurs in the range of load change.

3D solution predicts the critical load approximately 10% lower than 1D beam model solution. Figure 3 shows von Mises stress distribution which is substantially different from the one assumed in the beam bending model.