The mode shapes for sets of members are created automatically when calculating the critical load factor, 𝛼cr. To determine this factor, an internal planar framework model is created with four degrees of freedom at each node. An eigenvalue analysis is then run to find the governing stability conditions. The 𝛼cr factor further determines the set of members’ elastic critical moment for lateral-torsional buckling, Mcr.
The mode shapes are not available in numerical form. Use the Display factor to display the mode shape in an exaggerated graphical representation.