Mechanical APDL Basic Analysis Guide

Figure 7.5: Unaveraged PLETAB Contours

The PLLS command displays line element results in the form of contours. The command also requires
data to be stored in the element table. This type of display is commonly used for shear and moment
diagrams in beam analyses.

Notes

• You can produce isosurface contour displays by first setting Key on the /CTYPE command (Utility Menu>
  PlotCtrls> Style> Contours> Contour Style) to 1. See The Time-History Postprocessor (POST26) (p. 201)
  for more information about isosurfaces.


• Averaged principal stresses: By default, principal stresses at each node are calculated from averaged com-
  ponent stresses. You can reverse this, so that principal stresses are first calculated per element, then aver-
  aged at the nodes. To do so, use the following:
  Command(s):AVPRIN
  GUI: Main Menu> General Postproc> Options for Outp
  Utility Menu> List> Results> Options

This method is not normally used, but can be useful in special circumstances. Averaging operations
should not be done at nodal interfaces of differing materials.

• Vector sum data: These follow the same practice as the principal stresses. By default, the vector sum
  magnitude (square root of the sum of the squares) at each node is calculated from averaged compon-
  ents. By using the AVPRIN command, you can reverse this, so that the vector sum magnitudes are
  first calculated per element, then averaged at the nodes.


• Shell elements or layered shell elements: By default, results for shell or layered elements are assumed
  to be at the top surface of the shell or layer. To display results at the top, middle or bottom surface,
  use the SHELL command (Main Menu> General Postproc> Options for Outp). For layered elements,
  use the LAYER command (Main Menu> General Postproc> Options for Outp) to indicat e layer
  number.


• von Mises equivalent strains (EQV):The effective Poisson's ratio used in computing these quantities
  may be changed using the AVPRIN command.
  Command(s):AVPRIN
  GUI: Main Menu> General Postproc> Plot Results> Contour Plot> Nodal Solu
  Main Menu> General Postproc> Plot Results> Contour Plot> Element Solu
  Utility Menu> Plot> Results> Contour Plot> Elem Solution

Typically, you would set the effective Poisson's ratio to the input Poisson's ratio for elastic equi-

valent strain (item and component EPEL,EQV) and to 0.5 for inelastic strains (item and component

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The General Postprocessor (POST1)