Additional Beam Results: Written if Requested from Ansys LS-DYNA
Additional Beam Results: written if requested from Ansys LS-DYNA
In addition to the basic data components additional beam results may be output to the .THF file for both Belytschko-Schwer and Hughes-Lui beam elements. As no indication of the element type is written to the .THF file it is impossible for T/HIS to work out whether a specific element is a Belytschko-Schwer or a Hughes-Liu beam. As the element type is unknown the user must know which element type a beam is in order to extract the correct results.
Belytschko-Schwer Beams
If you have used Belytschko-Schwer beams with a resultant plastic material model
the following "plastic" results will also be written out to
.THF
file: (Note that these data are written even if the
*DATABASE_EXTENT_BINARY
card field <
beamip
> is not set - the
presence of a resultant beam material triggers their output automatically. This
is not the case for Hughes-Liu data components, for which output must be requested
explicitly, see below.)
Coordinate systems of results
Beam results are always output in the element local coordinate system. Only beams declared in "beam element time-history blocks" will be available.
"Extra" data components
Where "extra" results are written, and T/HIS cannot resolve unambiguously whether they are Belytschko-Schwer plastic data, or Hughes-Liu stress/strain data, it is your responsibility to interpret the results correctly .
Notes on beam data
Hughes-Liu (integrated) beams locate their integration point(s) at mid-span, and have a constant shear force and moment along their length.
The location and number of integration points through the thickness at mid span depends on the beam shape. See the *SECTION_BEAM keyword in the Ansys LS-DYNA manual for more information.
Belytschko-Schwer (resultant) beams calculate the moment variation along the beam, so may have different Myy and Mzz terms at ends one and two. This presents a problem when only the basic force and moment vector is written since only one Myy and one Mzz term are output. These are in fact the values at end 1. So if you have a cantilever fixed at end 2, with a point load at end 1, you will not see any moment in it if you only plot the basic Myy or Mzz data components (although the moment will be there and it will behave correctly). Furthermore, the sign of the end 1 Myy and Mzz moments written to the extra data slots is opposite to the sign of the basic moment vector Myy and Mzz moments so care must be taken in interpreting the direction of moments when switching between basic and extra data component moments.