All Element Property sets created are associated with an analysis preference. This preference is selected in the Preferences/Analysis menu. Make the appropriate selection before proceeding. Be aware that if the analysis preference is changed during a session, Patran will attempt to convert existing element property sets to the new preference environment. Converting back to the original preference will not necessarily restore the element property definitions to their original state. To run the same problem on different codes, while maintaining the original state of the element property definitions, copy the database, change the analysis preference, and make the appropriate changes to element properties, materials, loads, etc.

Element Property sets can be created, modified, deleted, and displayed. Set Modification is completely general in that this action essentially deletes the original set and replaces it with the modified set.

The Create option may also be used to Modify a set. The only difference is that you will be prompted with a message warning that the set already exists, and asking whether it should be overwritten.

Creating a new set that is a modification of an existing set is accomplished by creating a renamed set using the Create action.

The region of application on the model of the defined set is established using the standard selection tools. The ID of selected items is displayed in the Select Members databox. These members can be added or removed from the Application Region by pushing the appropriate button on the form. The Application Region listbox can also be edited directly. The Element Property set is applied to the members in the Application Region box, not the Select Members box.

The Option(s) portion of the form will vary with element type, as will the menu brought up by selecting Input Properties. The typical Input Properties menu has boxes for providing data values as well as specifying material and field names. To avoid confusion field names are prefixed by f: and material names by m:. Also, property inputs that are enclosed in [brackets] are optional, and need not be input if the defaults are applicable.

Element Property sets are associated with specific finite element types. See the preference guide or the user manual for discussions of the large number of specific element types and properties supported. Elements may be associated to only one element property set. Property sets that are associated directly to elements take precedence over property sets associated to elements through geometry.

The use of fields to define complex spatial data distributions, such as thickness distributions, is encouraged. Fields are created in the separate Fields application. The use of Discrete FEM Fields can be very helpful for properties that vary in value for many elements but can not be defined using a function. In general, Element Discrete FEM Fields should be used. There are cases where a Nodal Discrete FEM Field is more convenient. One such case is for a thickness which varies across the element. Care must be taken when using Nodal Discrete FEM Fields for property values that may not vary within a given element. In this case, the Field evaluator will average the values for each of the element nodes. This may result in unwanted values.

Material properties are created separately in the Materials application. Material properties must be defined prior to creating element property sets. Their existence is required to complete definition of the property set. If you don’t have the material properties yet, input a dummy material name in any required material property databox, and a blank material will automatically be created.

The PATRAN 2.5 Neutral File uses material numbers rather than material names. If a PATRAN 2.5 Neutral File is created under File/Export or Analysis translation, the material names supplied by the user will appear in the Neutral File as material numbers assigned in sequence by Patran. If a material number is significant to an analysis code using the Neutral File (e.g., a pointer to a materials library), the user should use an explicit material number instead of a name. For example, the material name “m:18” or “MATRL.18” will be passed to the Neutral File as material “18,” even if it is the only material in the database.