Hi Ana,

When the Load Multiplier is 1e-4, multiply the load by 1e-4 then rerun the analysis, you will get a more accurate estimate of the critical buckling load when the Load Multiplier is closer to 1.0

You have a panel with many flat rectangular membranes surrounded by ribs. Small loads buckle those membranes out of plane. Since there are hundreds of membranes, there are hundreds of closely spaced buckling modes. This is a local buckling mode. You may be more interested in a global buckling of the entire panel. For that, you will need to find a buckling mode that is much higher than those local buckling modes.

Is there a pressure load on the face of the panel? If so, a nonlinear Static Structural analysis (large deflection On) run upstream of the Eigenvalue Buckling would cause the membranes to be deflected slightly out of plane by the face pressure. Then the buckling caused by the line pressure on the top edge may generate higher Load Multipliers so you can more easily find the global panel buckling mode.