Use beam elements to model structures in which one dimension (the
length) is significantly greater than the other two dimensions and in which the
longitudinal stress is most important.
Beam theory is based on the assumption that the deformation of
the structure can be determined entirely from variables that are functions of
position along the structure's length. For beam theory to produce acceptable
results, the cross-section dimensions should be less than 1/10 of the
structure's typical axial dimension. The following are examples of typical
axial dimensions:
the distance between supports,
the distance between gross changes in cross-section, and
the wavelength of the highest vibration mode of interest.
Abaqus
beam elements assume that plane sections perpendicular to the axis of the beam
remain plane during deformation.
Do not be confused into thinking that the cross-section dimensions should
be less than 1/10 of a typical element length. A
highly refined mesh may contain beam elements whose length is less than their
cross-section dimensions, although this is not generally recommended—continuum
elements may be more suitable in such a case.