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The single element is taken out of the structure and considered as a single beam, with:
The end conditions for warping and torsion are defined as follows:
|
Cw_i |
Warping condition at end i (beginning of the member) |
|
Cw_j |
Warping condition at end j (end of the member) |
|
Ct_i |
Torsion condition at end i (beginning of the member) |
|
Ct_j |
Torsion condition at end j (end of the member) |
To take into account loading and stiffness of linked beams, see chapter "Linked Beams"”.
For this system, the elastic critical moment Mcr for lateral torsional buckling can be analyzed as the solution of an eigenvalue problem:
with
|
h |
Critical load factor |
|
Ke |
Elastic linear stiffness matrix |
|
Kg |
Geometrical stiffness matrix |
For members with arbitrary sections, the critical moment can be obtained in each section, with: (See Ref.[3],pp.176)
with
|
h |
Critical load factor |
|
Myy |
Bending moment around the strong axis |
|
Myy(x) |
Bending moment around the strong axis at position x |
|
Mcr(x) |
Critical moment at position x |
The calculated Mcr is then used in the Lateral Torsional Buckling check of SCIA Engineer.
For more background information, reference is made to Ref[2].