SFLEX
SFLEX, FFAX, FFBY, FFBZ, FFTO, FFTSY, FFTSZ
Sets flexibility factors for the currently defined pipe
element section.
FFAXFactor to increase axial flexibility. The default value is 1.0.
FFBYFactor to increase bending flexibility about element y axis (bending in the element x-z plane). The default value is 1.0.
FFBZFactor to increase bending flexibility about element z axis (bending in the element x-y plane). The default value is
FFBY.FFTOFactor to increase torsional flexibility. The default value is 1.0.
FFTSYFactor to increase transverse shear flexibility in the element x-z plane. The default value is 1.0.
FFTSZFactor to increase transverse shear flexibility in the element x-y plane. The default value is
FFTSY.
Notes
The SFLEX command sets section-flexibility factors for sections used by pipe elements.
To increase stiffness, use a flexibility factor of less than 1.0.
The FFBY and FFTSY arguments affect motion in the element x-z plane, and the FFBZ and FFTSZ arguments
affect motion in the element x-y plane. For stout pipe structures
with low slenderness ratios, set both FFBY and FFTSY--and/or both FFBZ
and FFTSZ (the related bending and transverse shear factors)--to the
same value to obtain the expected flexibility effect.
When issued, the SFLEX command applies to the pipe section most recently defined via the SECTYPE command.
SFLEX is valid only for linear material properties and small strain analyses. The command does not support offsets, temperature loading, or initial state loading. While the resulting displacements and reactions are valid, the stresses may not be valid.