Output Requests

Field Output and History Output

There are two classifications of output:

• Field output represents results across a large portion of the model. You can use field output to generate contour plots, isosurface plots, and symbol plots, and animations in Physics Results Explorer.
• History output represents results at specific points in the model or results that relate to the entire model or to model regions as a whole (such as energy). You can generate X–Y plots from history output in Physics Results Explorer.

Output Frequency

By default, the app writes field output at every increment of a step. Usually you are interested in only a small subset of all of this computed data. You can specify the data that you want saved to the database by creating output requests. An output request consists of the following information:

• The variables or variable components of interest.
• The region of the model (or points on the model) at which the values are recorded.
• The rate at which the variable or component values are recorded.

When you create the first step of the simulation, two default output requests are automatically created: one for field output and another for history output. These output requests preselect a default set of output variables corresponding to the type of step. For example, a static step preselects certain output variables such as stress, strain, and displacement, whereas a frequency step or linear perturbation step chooses different variables. You can see the default variables chosen by double-clicking the output request object to open it from the Feature Manager.

By default, output is requested from every node in the model and from default section points. In addition, the app selects the default rate at which the variable values are recorded to the database. You can edit and change these default output requests or create new ones.

Display of Output Requests in the Feature Manager

Output request objects are specific to a particular step in the simulation sequence, as shown in the Feature Manager. Default output requests and output requests that you have modified are propagated to subsequent steps in the analysis, for similar step types.

Whenever you create a new step in the simulation sequence, a new default field output request is created automatically for it, unless an existing output request is available from a previous similar step—in this case the existing output request is propagated into the new step. You can open and edit any existing or propagated output request to change the variables selected.