Creating Pressures

Pressures are intensive loads representing uniform scalar pressure fields applied to surface geometries, and characterized by the fact that the force direction is everywhere normal to the surface.
Pressure objects belong to Loads objects sets.

Units are pressure units (typically N/m2 in SI).

Pressures can be applied to the following types of Supports:

Mechanical Feature	Geometrical Feature				Analysis Feature
Mechanical Feature	Point or Vertex	Curve or Edge	Surface or Face	Volume or Part	Analysis Feature

This task shows how to create a Pressure applied to surface geometry.

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.

Before You Begin:
Go to View -> Render Style -> Customize View and make sure the Shading, Outlines and Materials options are active in the Custom View Modes dialog box.

1. Click the Pressure icon

The Pressure dialog box is displayed.

2. You can change the identifier of the Pressure by editing the Name field.

3. Set the value of the scalar pressure. A positive value describes a pressure whose resultant is directed towards the material side of the selected surface.

4. Activate the Data Mapping option to have the data mapping functionality available (only if you have ELFINI Structural Analysis product installed).

Data Mapping

	You can re-use data that are external data (experimental data or data coming from in-house codes or procedures). You can also integrate user loading knowledge and processes into this version.
	This data mapping is available for pressure, line loads, surface loads and volume loads.
	The selected external data file will be either a `.txt` file (columns separated using the `Tab` key) or a `.xls` file with a pre-defined format (four columns, the first three columns letting you specify X, Y and Z points coordinates in the global axis and the last one containing the amplification coefficient). Use the `Modify` switch button to load the desired external file.

5. Click the Browse switch button in the Pressure dialog box and load the desired external file. Make sure the file type is actually *.txt.

The FileBrowser dialog box lets you select the desired file: MappingFileExample.txt.

When you click Open, the Pressure dialog box is updated.

The Show button now lets you visualize the imported file inside the session. If you then modify the pointed file, the values are synchronized and the load feature invalidated.

Note that X, Y and Z columns allow you defining the length. The Coef value is not assigned a dimensional value. When creating the design table (either in .txt or in .xls format), if you define the desired unit in parentheses, in the first row, this using will be interpreted by the system.

The system starts reading the values at the second row of the .xls or .txt file. The first row allows you defining units (unit symbol written between parentheses). Otherwise, the system will use the default unit defined in the Options dialog box (Tools -> Options -> Parameters, Unit tab).

6. Select the geometry support (a face) on which you want to apply the Pressure. Any selectable geometry is highlighted when you pass the cursor over it.

You can select several supports in sequence, to apply the Pressure to all supports simultaneously.
Several arrows symbolizing the pressure are visualized.

7. Click OK to create the Pressure.
A Pressure object appears in the specification tree under the active Loads objects set.

	You can either select the surface and then set the pressure value, or set the pressure value and then select the surface.
	If you select other surfaces, you can create as many Pressure Loads as desired with the same dialog box. A series of Pressures can therefore be created quickly.
	Loads are required for Stress Analysis computations.
	If several Analysis Cases have been defined in the Finite Element Model, you must activate a Loads objects set in the features tree before creating a Pressure object (only available if you have ELFINI Structural Analysis product installed).
	Pressure objects can be edited by a double click on the corresponding object or icon in the specification tree.

Make sure the computation is finished before starting any of the following operations.

Products Available in Analysis Workbench

The ELFINI Structural Analysis product offers the following additional feature with a right mouse click (key 3):

on a Pressure object:

Pressure visualization on mesh: the translation of your Pressure object specifications into solver specifications can be visualized symbolically at the impacted mesh elements, provided the mesh has been previously generated via a Compute action.

Right-click on a Pressure object and select the Pressure visualization on mesh option.

on a Loads objects set:

1) Generate Image: generates an image of the computed Load objects (along with translating all user-defined Loads specs into explicit solver commands on mesh entities), by generating symbols for the elementary loads imposed by the Loads objects set. The image can be edited to include part or all of the options available.

Right-click on a Loads objects set and select the Generate Image option. The Image Choice dialog box is displayed. You can select images by clicking them in the list.

The resulting images sequence is obtained by superposition.

2) Report: the partial status and results of intermediate . pre-processor computations are reported in HTML format. It represents a subset of the global Report capability and generates a partial report of the Loads objects set Computation.

Click the Basic Analysis Report icon on the bottom toolbar. The .html partial report file is displayed.

3) Double-clicking on the Loads set, you will display the Loads dialog box that lets you choose whether you wish to apply self-balancing to the load. Example of use: if this option is used with iso-static specifications, it will allow you to simulate free-body loading. If you make the option active, the center of inertia results null.