Calculix_2.20_4win default solver spooles

i have read the paper and it is very interesting,
to have results with a simplified assumption and calculation.
in standards the initial geometrical imperfection is
pre-deformation from the buckling figure or self-weight with gravity.
Additional you have to apply residual stress. Material is bilinear,
i think like in the paper.
With these conditions you can calculate the load bearing capacity of common steel beams,
called the yield zone theory. And with the results you can recalculate the buckling curves,
according to slenderness and cross-sections.
In EC and DIN standards the buckling curves are empirical values
and thus all effects should be included (Bernoulli, Timo, Johnson’s parabolic ).

wbr

@dichtstoff

Hi,
There are other aproachs in which you don’t need to apply residual stresses.
I’m not sure if the forum is the place or we should discuss this privately as this is more related to the application of a procedure described in a design code than ccx itself.

The method I’m talking about is described among others in DNV-RP-C208 Non-linear FE analysis Methods / 5.4.2 Determination of buckling resistance by use of linearized buckling values and it’s corresponding B.3 Example: Determination of buckling resistance by use of linearized buckling values.If you are familiar with EC3 curves you will get it on the fly.

Three other procedures are also described and exemplified, each one more interesting. I think it’s worth you take a look at that excellent DNV Recommended practice.

If you are more interested in shells , DNV-RP-C202 Buckling strength of shells deals with buckling stability of shell structures based on the load and resistance factor design format (LRFD).