Member analysis - Interpretation of MNA and GMNIA results

Ultimate limit state

The ultimate limit state is reached when the strain for buckling susceptible members has reached 5% or when the solver stops converging because the maximum load has been reached. 

Using the LBA analysis,  factor α_cr (smaller or greater than 15) tells you whether to use only the MNA or GMNIA analyses.

LBA >15: only MNA (materially non-linear analysis) is needed (100% applied) and the results for the MNA Plates have to be less than 5 %

LBA <15: MNA is a must, the  GMNIA (Geometrically and materially nonlinear analysis with imperfections)  is needed, and the GMNIA Plates' results (including the imperfections) must be less than 5 %.

Serviceability limit state

Design codes provide limits for deflection in the serviceability limit state. These can be checked by comparing the deflection of the analyzed members to the limits. 

u_sum - vector sum of deflection (u_x, u_y, u_z) at the given point

Watch our product engineer Vit modeling a transverse beam of a railway bridge and analyzing it in Member.