29.1.2 Understanding how to specify an X–Y data object

To specify an X–Y data object, you first choose the source of the data and then provide any necessary details. Possible sources are:

ODB history output

Select this method to specify an X–Y data object by reading history output results from an output database. You can specify which variables to read from the output database, from which steps of the analysis to read, and the frequency at which to read the data; for example, you can read every third data point. You can also specify a numeric form for any complex-valued output data. For more information, see Reading X–Y data from output database history output, Section 29.2.1.

ODB field output

Select this method to specify an X–Y data object by reading field output results from an output database. You can specify which variables to read from the output database and for which elements or nodes to read the data. ABAQUS/CAE extracts results from the currently active steps and frames; see Activating and deactivating steps and frames, Section 24.3.1, for more information. You can also specify a numeric form for any complex-valued output data. For more information, see Reading X–Y data from output database field output, Section 29.2.2.

Operate on X–Y data

Select this method to derive a new X–Y data object by manipulating previously saved X–Y data objects. You specify the new X–Y data object by applying functions and mathematical operations to existing data. An example of a function is Combine. If you Combine an X–Y data object containing stress versus time with an X–Y data object containing strain versus time, you produce an X–Y data object containing stress versus strain at equivalent times. For more information, see Operating on saved X–Y data objects, Section 29.4.

ASCII file

Select this method to read X- and Y-values from an existing text file. The file can contain more than two columns of data, separated by commas, spaces, or tabs; and you can specify which columns correspond to the X- and Y-axis data. In addition, you can specify the frequency at which the data should be read from the file; for example, every third row. For more information, see Reading X–Y data from an ASCII file, Section 29.2.3.

Keyboard

Select this method to manually type X- and Y-values into a simple table editor. Within this method, ABAQUS supports several special editing techniques, as well as an option to read data from a file. For more information on this topic, see Entering X–Y data from the keyboard, Section 29.2.4.

Path

Select this method to specify an X–Y data object by reading field output results at locations along a path through your model. ABAQUS obtains results from an output database. You can specify the points, elements, or edges that make up the path and the step, frame, and variable for which to obtain results. For more information, see Chapter 31, Viewing results along a path.”

In addition, you can create an X–Y data object while using the table editor to create a material in the Property module. For more information, see Entering tabular data, Section 3.2.7.

Once you have specified your X–Y data object, you can save it or you can display it in the form of an X–Y plot. Saving the X–Y data object allows you to subsequently plot, edit, rename, delete, or operate on it; it also allows you to copy the X–Y data object to an output database file for use in later ABAQUS sessions. For X–Y data originating from sources other than output database history output, you must save your data to later produce an X–Y plot containing multiple data objects. Saved X–Y data objects are retained only for the duration of the session. For the X–Y data object to be persistent across sessions, you must copy it to an output database file.

If you have copied an X–Y data object to your output database file during an earlier session, you can access that object when you open the file in the current session. You can display the X–Y data object in the form of an X–Y plot, just as you can any other specified objects. To edit, rename, delete, or operate on a data object that was created in a previous session, you must load it to the current session.