Computing Objects Sets

A finite element computation is a succession of data manipulation processes in which input data resulting from a previous process (or directly input by the user) is converted into output data ready to be used by a subsequent process. Such ready-to-use data is stored in program objects sets such as those appearing in the analysis features tree under Analysis Cases (Restraints, Loads, Masses, Solutions) objects sets.

When data contained in such an objects set is ready for use in the subsequent finite element computation process, the object has been computed and can be analyzed. Thus, Computing an objects set consists in generating finite elements results for all objects and objects sets necessary to analyze the specified objects set.

The computation of an objects set requires two distinct actions:

First, the user-defined specifications attached to each object belonging to the objects set in the specification tree must be translated by the pre-processor into solver-interpretable commands.
Since solvers can only interpret data applied on mesh entities (nodes and elements), this first translation step requires the existence of a mesh support for converting user input specifications on the geometry into explicit solver commands on nodes and elements.

Next, the solver translates the solver commands into data ready for algorithmic treatment as required by the numeric procedure invoked.
Since algorithms deal only with operators dimensioned by the problem size (number of degrees of freedom (degree of freedom)), this second translation step requires the exact knowledge of the behavioral hypotheses of the finite elements (properties), which contain the required degree of freedom information.

As a result of such action, the program translates the user-defined specifications into solver-interpretable commands applied on mesh entities, and you can visualize on the mesh the result of this translation. This analysis capability, used especially for displaying program feedback on applied Restraints, Loads or Masses objects in the case of large size models (when you do not wish the entire computation to be performed), is available with a right (key 3) click on:

Restraint, Load and Mass type objects, in the form of the object Visualization on Mesh action

Restraints, Loads, Masses and Solutions objects sets, in the form of the following objects set actions:

	objects set Image Generation
	objects set Reporting

A prerequisite to these actions is the existence of a Mesh.

Avoid having CATAnalysis documents automatically saved. For this, go to Tools->Options->General (menu bar) and de-activate the Automatic save every xx minutes option. Otherwise, on some models, each computation will be followed by a Save, thus making temporary data become persistent data.

This task shows how to compute a Mesh.

Computing a Mesh will enable the analysis of any object of Restraints, Loads and Masses type, without requiring the computation of a Solution.

You can use the sample00.CATAnalysis document from the samples directory for this task: Finite Element Model containing a Static Analysis Case and computed corresponding Static Solution.

1. Click the Compute icon

.
The Compute dialog box is displayed.

The combo box allows you to choose between several options for the set of objects to update:

All: all objects defined in the analysis features tree will be computed.

Mesh Only: only the mesh will be computed.

The ELFINI Structural Analysis product offers the following additional feature:

	`Analysis Case Solution Selection`: only a selection of user-specified Analysis Case Solutions will be computed, with an optimal parallel computation strategy.
	`Selection by Restraint`: only the selected characteristics will be computed (Properties, Loads, Masses).

The Preview switch allows you to obtain an estimate of the time and memory required to perform the computation.

2. Select Mesh Only.

3. Click OK in the Compute dialog box.
The Mesh is computed and can be visualized.

The status of the Nodes and Elements objects set is changed to valid in the analysis features tree.

A valid Mesh object also appears under the Nodes and Elements objects set.

Any object in the Finite Element Model can now be analyzed (visualized on the Mesh).

By extension, all objects belonging to any objects set in the Finite Element Model can also be analyzed (visualized in various Generated Images or analyzed in a Report).

For mode details on object Visualization on Mesh and on objects set Report and Image Generation, see the creation of objects of Restraints, Loads and Masses types.

You can change the definition parameters of an object either by replacing it by a new one (delete followed by create) or by modifying it (edit the definition parameters).

To edit the definition parameters of an object, activate it in the analysis features tree and double-click the object (or right-click, then click .Object -> Definition ) to re-display the object definition dialog box.