Selecting section point data by category

When you are displaying a contour plot, you can use the Section Points dialog box to control the section points from which Abaqus obtains integration point results and material orientations by selecting a category and the section points that represent the bottom and top locations.

This task shows you how to:

See Also
Selecting model data and analysis results to plot

Context:

Reinforcement (rebar) layers in membrane, shell, and surface elements are treated as section points for output purposes; each reinforcement layer has a unique name. For example, you can request results from the section points at the top surfaces of certain shells in the model, from the middle section points of certain beams in the model, or from a named reinforcement layer in certain membrane elements in the model.

Contour plots displaying output at two section points vary in appearance depending on the type of shell. In a conventional shell the two contours appear as a double-sided shell with different contours on each side, while in a continuum shell (or a composite solid) the two contours appear as distinct two-dimensional contour fronts at each section point location. Axisymmetric shells, which are composed of line elements swept to form a three-dimensional surface, exhibit neither behavior because they are not considered three-dimensional shells; instead, these shells display output at a single section point only.

In many cases the location of a section point is described in terms of its position relative to the midpoint of the cross-section. For two-dimensional beams this relative position is reported as a fraction of the distance between the midpoint of the cross-section and the top or bottom surface of the section. For shells this relative position is reported as a fraction of the distance between the midpoint of the cross-section and the SPOS or SNEG surface of the section. Reinforcement layers are indicated by their unique name.

For beams with three-dimensional sections, the relative position of a section point can be reported as a fraction of the distance between the midpoint of the cross-section and

  • the top or bottom of the section (along the local 2-axis of the section) or

  • the left or right side of the section (along the local 1-axis of the section).

For circular beams the section point locations are defined as a relative position with respect to the section radius and an angle rotated from the positive 1-axis about the midpoint of the cross-section.

For more information about where section points are located in different section types, see the following:

For more information about reinforcement layers, see Defining Reinforcement.

Abaqus/CAE provides the following methods for choosing the section points to display:

  • Display a category of elements and a location. Examples of element categories include element types and materials. The location can be the top or bottom surface or both.

  • Display the section point containing the critical value (absolute maximum, maximum, or minimum). Abaqus/CAE searches for the critical value across all of the section points in each element. The resulting plot is called an envelope plot.

Select the section point using categories and a location

  1. Display a contour plot of the desired field output variable. For more information, see Producing a contour plot.
  2. Locate the Section Points dialog box.

    From the main menu bar, select ResultSection Points.

    The Section Points dialog box appears.

  3. From the Selection method field, select Categories.

    The elements within each category share common section properties, such as the following:

    • The section type associated with the elements in this category.

    • The material name or composite specification included in the section definition.

    • The number of section points through the section.

    • The cross-section geometry (beams only).

  4. From the Active locations field, select Bottom or Top to activate only the Bottom Location or Top Location section point. For contour plots of integration point variables on three-dimensional shells or composite solids, select Top and bottom to display output simultaneously at both section points. Only contour plots of this type can display output for both section points simultaneously; in all other contexts, Abaqus/CAE displays output only at the Bottom Location section point when you select Top and bottom.

    Abaqus/CAE displays output only at active locations. The Bottom Location and Top Location fields display the two section points at which you can display output for the selected category. By default, these fields display the SNEG and SPOS section points, respectively.

  5. In the Category table, select the element category or categories for which you want to change the output location and select the location. If you selected Top and bottom from the Active locations field, select both locations.

    The Available Section Points in Cross-Section field in the bottom half of the dialog box lists the section points from which output was saved for the category and location you have selected. If you have selected more than one category, only those locations that are common to all of the selected categories appear in the list.

  6. In the Available Section Points in Cross-Section field, select the section point location to display.
  7. Click Apply to view your settings.

    The model plot in the current viewport changes to display values from the specified section points. The plot legend, if active, changes to identify the specified section points. For information about the plot legend, see Customizing the legend.

    Results for subsequent contour, symbol, and material orientation plots; tabular reports; model probing; and X–Y data objects along a path will be obtained from the section points you have specified.

  8. Click OK to select the section points and to exit the dialog box.

Select the section point containing the critical value

  1. Display a contour plot of the desired field output variable. For more information, see Producing a contour plot.
  2. Locate the Section Points dialog box.

    From the main menu bar, select ResultSection Points.

    The Section Points dialog box appears.

  3. From the Selection method radio buttons, select Categories.
  4. From the Active locations radio buttons, select Envelope.
  5. From the Criteria field of the dialog box, select the criterion (absolute maximum, maximum, or minimum) that will determine the section point containing the critical value.
  6. From the Position field, select the algorithm that Abaqus/CAE will use to determine the section point containing the critical value.

    • If you choose Integration point, Abaqus/CAE compares the value at all of the integration points of each section.

    • If you choose Centroid, Abaqus/CAE compares the value averaged at the centroid of each section.

    • If you choose Element nodal, Abaqus/CAE compares the value extrapolated to the nodes of each section.

  7. Click Apply to view your settings.

    The model plot in the current viewport displays the critical section point and its value for each element in the mesh. For information about the plot legend, see Customizing the legend.

  8. If you are displaying a composite layup, you can determine how Abaqus/CAE displays the critical section point by selecting ply options for the contour plot.
    1. From the main menu, select OptionsContour.
    2. From the Contour Plot Options dialog box that appears, click the Other tab.
    3. From the options at the bottom of the tabbed page, do the following:

      • Toggle on Show labels of plies that match criteria to see labels for the critical plies in the contour plot.

      • Toggle on Color by plies that match criteria to change the value that is being contoured from the field output variable to a ply name. The contour plot updates to show the critical plies in the model. The legend updates to show the names of the plies that are being displayed.

  9. Click OK to retain your settings and to exit the dialog box.