critcal moment abaqus

[hasanfal]

Hello, I would like to calculate the critical moment in Abaqus in order to compare it with the critical moment (for lateral torsional buckling) obtained from analytical calculations. The two values do not match. I calculate the critical moment in Abaqus by multiplying the eigenvalue of the buckling mode with the applied load and then multiplying this load by the distance, Can someone help me understand why I have this problem?

 

[FEA way]

Hard to say without knowing anything about your model and results.

 

[hasanfal]

I model a castellated beam with a length of 24 m with 2 concentrated loads in the third of the length and try to change parameters such as the opening size and examine what changes. That's why I would like to represent the deviation from critical moment analytically and numerically, but the deviation is very large, in abaqus the value of critical moment is 1270 kN.m and from analytical calculation 600 kN.m