XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX''"> Creating Material Property Models
A material model is a group of material properties that describe what your model is made of (such as steel or a composite) and the attributes of that material (stiffness, density, and so on). Once the materials for your model are defined, you will use the Element Properties application to assign them to model regions.
The Materials Application Form
The Materials application is where you define the materials for your analysis model. Patran provides options for creating and modifying an enormous number of material models. The Input Options subform is where you specify most of the material properties information. There are many Constitutive Models and material property value options available. The input options that appear and the values that you select for them depend on factors such as your analysis code and solution type equations.
To use the Materials Application form:
1. Click the Materials button on the Patran Main form.
The Materials application form appears in your viewport.
2. Select an Action, Object, and Method from the drop-down menus at the top of the form.
The bottom portion of the form varies depending on your selections for action, object, and method.
Actions
Use actions to create, show, modify, and delete material models. Action describes the action choices on the Materials Application form.
Action Descriptions |
Create | Input analysis code-specific material property data and associate that data with selected FEM or geometric entities. |
Modify | Make any change desired to Existing Materials Property Data. |
Delete | Remove material property sets from the database. |
Show | Display tables listing material properties. |
Objects
The objects are the types of material models that you have available. The following table summarizes the object chioces.
Object Descriptions |
Isotropic | Use for materials whose properties are the same in all directions. |
2D Orthotropic | Use for materials whose properties vary in orthogonal directions. |
3D Orthotropic | Use for materials whose properties vary in orthogonal directions. |
2D Anisotropic | Use for materials that vary in arbitrary directions. |
3D Anisotropic | Use for materials that vary in arbitrary directions. |
Composite | Layered materials with or without varying directional properties. |
Methods
The Method defines how you create a material model. You may start your model in one of two ways:
• Manual Input on the Input Options subform. An existing material may be used as a template to create a new material.
• Externally Defined, to define and assign materials in name only. This permits property data to be included in run files external to Patran.
The Methods table briefly describes the methods you may select.
Method Descriptions |
Manual Input | The Input Options form is used to input material property data. The data required varies depending on the analysis code, solution type, and constitutive model. |
Externally Defined | The material is defined in an external file.The Input Options form is not required. |
Sample Materials Forms
The following is a sample of a manual input of isotropic material properties.
Sample Manual Input Form
A sample Materials form is shown, for the selection Create/Isotropic/Manual Input. The selected Analysis Code and Type are MD Nastran /Structural. Once you have selected the Input Properties button located at the bottom of the Materials application form, a separate Input Options subform appears in the viewport. Every time you pres the Apply button a new constitutive material model is created based on the setting in the Input Options form.
A description of the data widgets on this form follows.
Existing Materials | Chooses a material from here to transfer it to the Material Name text box. |
Material Name | Defines a unique name (1-31 characters) for the material and automatically assigns a sequential Material ID number. |
Description | User-supplied descriptions of a selected material are displayed here for reference (1-256 characters). By default, the time and date of creation appears. |
Preference and Type | The Analysis Preference and Type appear. Check for correctness. |
Input Properties | Brings up the Input Properties form to input values for properties of this material. |
Change Material Status | Brings up the Change Material Status form to enable and disable material
model definitions. |
Sample Input Options Subform
Once you select Manual Input as the Method on the Materials application form, you must select and fill out the Input Options form for the material. Most of the Input Options forms are similar to the one shown below. There is a Constitutive Model plus other option selections, followed by databoxes to input specific property parameters. When you can use fields, a list of available Material Property Fields appears.
Constitutive Model | Selects a Constitutive Model from the unfold box. A single material may have several active constitutive models. |
Material Property Values | Input the values necessary to define the material model. This is just an example; the actual form displayed depends on the analysis code and type. |
Current Constitutive Models | The existing constitutive models and their status (i.e., active or inactive) appear here. Once you complete this form and select Apply, the newly created set appears here. |
Note: | To define more than one constitutive model for a material, fill out the form more than once, pressing Apply each time. |
Sample Constitutive Model Status form
A single Material can have several Constitutive Models defined, such as an elastic representation and an inelastic one. The constitutive model used in the analysis is determined by the Constitutive Model Status.
Existing constitutive models of an existing material appear in either the Active or Inactive list box depending on their current status. Selecting a model in either listbox automatically moves it to the other one.
