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Member analysis - Interpretation of MNA and GMNIA results

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IDEA StatiCa Member offers MNA (materially non-linear analysis) and GMNIA (geometrically and materially nonlinear analysis with imperfections) analyses of members subjected to buckling issues. To check these results, most design codes recognize two limit states – serviceability and ultimate.

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.