The definition of boundary conditions is one of the most difficult tasks of modeling in any software. IDEA StatiCa Member works with part of your structure which is “cut-off” from your global 3D FEA model. Therefore, the program lets the definition of boundary conditions on the judgment of an engineer.
In IDEA StatiCa Member you can define boundary conditions at the ends of related members. The application offers to input:
a) Supports – definition of supports should correspond to your 3D FEA model
b) End forces on related members – correspond to internal forces calculated in the standard 3D FEA program
It is not possible to input only End forces on related members without using supports. A more precise model (e.g. local eccentricities of members, real lengths of members are taken into account ) is used. Thus the imposed imperfections for the GMNIA analysis cause that the equilibrium is not preserved and mechanism may, therefore, be defined.
Reasonable support based on structural engineer judgment is recommended.
c) Supports + End forces on related members – minimal reasonable supporting based on structural engineer judgment + add internal forces from your 3D FEA program.