- Path data X-values
You can choose to form X-values based only on the points you have specified for the path or to additionally include all locations at which the path intersects the model. (An intersection occurs where the path crosses an element face, element edge, surface face, or surface edge. You can omit individual intersections from the path definition if the intersection lies within a user-specified distance of an actual data point. You can set this intersection tolerance value using Abaqus Scripting Interface commands; for more information, see Will link to ker-session-xy-pyc.)
You can also choose whether Abaqus/CAE interprets the points that make up the path as locations on the undeformed or the deformed model shape. When the deformed model shape is chosen, Abaqus/CAE computes the deformed coordinates at a node as the sum of the base coordinates and the deformation at that node multiplied by the viewport-specific deformation scale factor. Node list labels and edge lists indicate model locations and are equally applicable to the undeformed or the deformed model shape. Point list and circular path coordinates are fixed locations independent of the model geometry. Abaqus does not form data pairs for points that do not coincide with the model shape you have chosen.
The node labels or point coordinates that comprise a path are usually not in a form suitable for direct use as X-values. Abaqus/CAE offers several options for you to convert this series of points to useful X-values and subsequent X–Y plot axis labels. You can choose one of the following options to convert path points to X-values:
True distance: X-values correspond to each point's actual distance along the path in model space coordinates, starting with zero.
Normalized distance: X-values correspond to each point's distance along the path as a fraction of the total length of the path.
Sequence ID: X-values correspond to the order in which each point occurs in the path result list.
X, Y, or Z distance: X-values correspond to each point's actual distance along the path in the single coordinate direction you specify, starting with zero. This option is particularly useful for generating a plot of results versus radius in an axisymmetric model.
X, Y, or Z coordinate: X-values correspond to each point's distance from the origin along the axis you specify.
- Path data Y-values
You can control data pair Y-values by choosing the results step, frame, and field output variable for which Abaqus/CAE obtains results and by controlling how Abaqus/CAE computes certain types of results, as follows:
For node-based field output variables such as displacement to be obtained at nodal locations, Abaqus/CAE reads results directly from the output database with no further computations.
For element-based field output variables such as stress or strain to be obtained at nodal locations, Abaqus/CAE reads results from the output database, extrapolates those values to the nodes, then conditionally averages multiple contributions according to options you select.
For both node-based and element-based variables to be obtained at path points that do not coincide with nodal locations, Abaqus/CAE computes values by interpolating from the nodes to the requested location using a geometric approximation of the element's shape. You cannot control this computation.
The averaging options for element-based variables and the complex form options for complex number values are located in the Result Options dialog box. Averaging reduces multiple contributions into a single value. When you select result options to partially or fully suppress averaging, path points receiving multiple contributions produce multiple data pairs. Such data pairs share the same X-value but have a separate Y-value for each contribution. Depending on your path and on the characteristics of your model, the following techniques may be necessary to avoid multiple data pairs sharing the same X-value:
Set result options to fully enable averaging.
Set result options to ignore region boundaries when computing values.
Avoid paths that traverse region discontinuities.
Avoid paths along a line separating discontinuous regions.
Use display groups to isolate individual regions prior to obtaining results along a path.
Avoid point list paths that traverse one or more spatial points that lie visually outside of highly deformed elements and cylindrical elements that subtend a large angle but, due to isoparametric mapping, lie mathematically inside the elements. Such spatial points tend to be shared by two or more elements, leading to multiple Y-values.
For more information on value averaging, see Understanding result value averaging.
The Y-value of the data pairs is affected by the current complex form if your selected field output variable contains complex number results. An abbreviation of the complex form is appended to the Y-axis title when you plot the path. For example, if S-Mises is the selected field output variable and Magnitude is the complex form, the Y-axis title is S-Mises CPX:Mg. Other complex forms are similarly abbreviated. For more information on complex forms, see Controlling the form of complex results.
Abaqus/CAE does not form data pairs for points that do not have results for the specified step, frame, or field output variable.
|