Patran Users Guide > Loads and Boundary Conditions > Using Fields
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Using Fields
In some analysis models, particular input options for element properties, material properties, or loads and boundary conditions are not constant; they vary as a function of spatial, time, temperature, and other changes. Fields are used in these situations. Examples are a shell element whose thickness varies spatially, a pressure pulse load that is time-dependent, and a material property that is temperature- or stress-dependent.
The Fields Application Form
The structure of fields is flexible and generalized. You can create them from tabular input, mathematical relationships expressed in PCL, or from scalar/vector results on a collection of finite elements. The Fields application in Patran provides intuitive forms that lead you through the creation and modification of fields. Once you have created the field that you need, select it in a databox on one of the functional assignment application forms or input options forms.
To use the Fields Application form:
1. Select Fields from the Patran Main form.
The Fields application form appears in your viewport.
2. From the drop-down menus, select an Action, Object, and Method.
The remainder of the form varies depending on these selections.
Actions
The table below briefly describes the choices for Action on the Fields form.
Action Descriptions
Create
Creates a new field that can be Spatial, Material Property, or Non-Spatial. You can base the new field on an existing field. Most fields are made up of tabular data or PCL functions.
Show
Displays all fields set data in a table format.
Modify
Modifies the contents of an existing field.
Delete
Removes selected fields.
Objects
The table below briefly describes three types of fields that you can select as Objects on the Fields application form.
Field Type
Description
Spatial
Spatial fields define location-dependent pressures and temperatures in the LBCs application. You can also use them to define element property characteristics, such as thickness. They also define displacements and other loads. Spatial fields can be scalar or vector in nature. You can specify their application region in either real or parametric space, over one, two or three dimensions. You can apply multiple spatial fields at the same time.
Non-Spatial
Non-Spatial Fields specify time- and frequency-dependent loads and boundary conditions, and frequency-dependent material properties.
Material
Property
Select these fields on the Input Options form for the Materials application for properties such as modulus, CTE, etc. These fields can be one-, two-, or three-dimensional, with independent variables such as temperature, strain, strain rate, time, and frequency (singly or in combination).
Methods
The following table briefly describes the method of data input that you may select as Method on the Fields application form.
 
Field Type
Description
PCL Function
Uses a PCL expression to define the field values.
Tabular Input
Extracts data from a table to define the field values.
General Field
You can use the General Field to create a field for any Object type. The field data is described by a mathematical function composed in PCL.
FEM
FEM Fields are associated to a finite element model. Using this method you can map data from one analysis to create LBCs for your current model.
Sample Fields Form
The form for Create/Spatial/PCL Function creates scalar or vector spatial fields in real or parametric space, using a PCL expression or externally defined PCL function. Select Apply to create the field, then wait for the new field name to appear in the Existing Fields databox.
A list of widget descriptions follows.
 
Widgets
 
Existing Fields
Previously defined fields appear here. Select one with the Create Action if you wish to base a new field on an existing field. Select with Modify to change an existing field. The selected field name appears in the Field Name box below.
Field Name
Modify an existing field name, or enter a new field name here.
Field Type
Select Scalar or Vector. The form changes, depending on the pick.
Coordinate System Type
Select Real if the field is in X,Y,Z space, Parametric if it is in C1, C2, C3 space.
Scalar Function
Input a PCL command defining the field or name of the external PCL function file.