In the first part of this series I wrote something to the theoretical foundations. In this part there is now little practical emphasis. But first a little theory.
I had attachments so that small on a critical load factor of 10, the second-order theory to be considered. But what does exactly the number of critical load factor?
This is actually quite simple. If we increase the load to the critical load factor, then the system is unstable. Here is a very simple structural system:
What I said now the Verzeigungslastfaktor? It must be 3 different areas are distinguished:
- The critical load factor is less than 1 .
- The critical load factor is 1-10 .
- The critical load factor is greater than 10 .
The 2nd Case in practice, the most common case. The structure is under load once stable, but further evidence of stability is required. It must therefore be expected to second-order theory, or it must be buckling out after the replacement staff procedures. In the 3rd
Case, the structural stability is not endangered. There, a simple stress analysis with the internal forces to first-order theory.
If the buckling load factor greater than 1, that is so far no evidence against buckling or stability failure against another.
Two things are to be set.
The bar elements in RFEM can represent no lateral torsional buckling. This is indeed in almost all staff members of other programs. If there is a lateral torsional buckling problem could, therefore, further investigations are then necessary.
The determination of the critical load factor is carried out by solving an eigenvalue problem. In the "normal" calculation is important to note that any non-linearity is taken into account. If allso precipitated rods, precipitating beddings and other non-linearities in the system, then the calculation is at least inaccurate, possibly even incorrect. In this case, helps further the nonlinear analysis of RF-STABLE. More on that in the next part of this series.
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