Bulging stiffness

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The buckling stiffness is a term from the stability theory of structural engineering . She stiffened beulgefährdete carrier , thus providing a part of the load-bearing capacity , restore lost through the bumps. Typical examples are webs of high girders in steel bridge construction and the stiffening of cylindrical sheets by stringers in aircraft construction .

species

There are two types of buckling stiffeners:

  • The longitudinal stiffness goes along the beam and significantly increases the load-bearing capacity.
    • Open cross-sections save more steel, for them a proof against lateral torsional buckling has to be carried out by maintaining a certain ratio of width to height. For more details see u.
    • Closed cross-sections can be installed more quickly.
  • The transverse stiffener only increases the load-bearing capacity when the distance is very close and is rarely used.

According to Eurocode  1993-1-5, the verification is carried out as follows: The longitudinal stiffener divides the buckling field into individual fields. The effective width is calculated for the width of the individual fields. So a piece is missing in the middle of the fields. Two effective widths border on each stiffener and one on the flange . Then a reduction factor is calculated from the entire bulge area. With these, the effective widths on the longitudinal stiffeners are reduced a second time, but the effective widths on the flanges are not. This gives the effective cross section. In DIN 18800-3, only single field buckling is dealt with.