Material properties must be defined for each part in the model. This is done by right-clicking on the "Material" heading for that part in the tree view and selecting the "Edit Material…"
command. A dialog will appear allowing you to define the relevant properties. Not all of the properties are necessary for every model. For example, you only need to define the modulus of elasticity, the Poisson's ratio, and a coefficient of thermal expansion if you are performing a thermal stress analysis – optionally include the density if an acceleration or gravity load is to be specified. For a stress analysis without thermal effects, the coefficient of thermal expansion is not needed.
Some element types support multiple material models. The material model is defined in the
"Material model" drop-down box in the "Element Definition" dialog which is accessed by right-clicking on the "Element Definition" heading for that part in the tree view and selecting the "Edit Element Definition..." command. A table with all of the material models available for each element is available in Appendix D.
The material library manager allows tracking of predefined or user defined materials by use of a database format. Material data can be imported or exported to and from XML files. Many of the material properties have been provided by MatWeb®. To access the library manager from the FEA Editor environment, select the "Tools" then click on the "Manage Material Library" button in the "Options" panel. The dialog shown in Figure 2.14 will appear:
Figure 2.14: Material Library Manager Dialog
A pre-defined database called the Autodesk Simulation Material Library already exists. This database cannot be altered. To view the different material properties select a material (Aluminum 6061-T6; 6061-T651 for example). The material properties will appear in the table to the right. This table contains the information for the defined material. In the
"Material Identification" section, the material library and the material model are identified.
The material model is selected when the entry for the material is added. This will be discussed later. Also in this section are the material name and material description. The rest of the table contains the material properties associated with the material model selected. For Aluminum 6061-T6; 6061-T651 the material model selected was "Standard". As seen in Figure 2.12, properties for the "Standard" material model include general properties (mass density and damping), elastic, thermal, electrical and plastic properties. Not all information is needed for every analysis. For example, if a new material for a static stress analysis is needed, then you should only need to enter data for the elastic properties.
Since this is a material from the Autodesk Simulation Material Library, editing properties is not allowed. The next section will describe how to enter properties for user materials. The database format for the libraries is a FoxPro (.dbf) file format. These files can be changed with the Material Library Manager, FoxPro or Visual Basic.
Adding Material Libraries and Material Properties
To create a library, press the "New …" button at the top of the dialog. The dialog shown in Figure 2.15 will appear.
Figure 2.15: Create Library Dialog
This dialog allows the user to create the name of the new library. In the "File name" field enter a library name and then press the "Save" button. The next dialog will appear.
Figure 2.16: Create Library Dialog
This dialog is a prompt to enter a description for the library. For example, in the predefined library, the description is "Autodesk Simulation Material Library". After typing in a description press the "OK" button to return to the "Material Library Manager" dialog.
Notice that a new tab exists for the new library. This is set as the active library.
To add a material, right-click on the heading for the library in the tree view and select the
"Add New Material" command. The dialog shown in Figure 2.17 will appear.
Figure 2.17: New Material Dialog
Type the name of the material in the "Material name" field. Choose the type of material model in the "Material model" drop-down box and select a unit system in the "Unit System"
drop-down box. If the material is entered in one unit system and the model is in a different unit system, the software will automatically make the appropriate conversions. This means that the material information can be in "English (in)" and the model can be in "Metric mks (SI)". In the "Material Description" field, enter a description of the material that is being added. It is suggested that a reference to the source of information for the material should be entered in the
"Material source description" field. Once this information is specified, press the "OK"
button. The screen shown in Figure 2.18 will appear.
Figure 2.18: Material Property Entry Dialog for a Standard Material Model
The next step is to enter the material properties needed. You can then repeat the process to add more materials to the library. Once you are finished, close the Material Library Manager.
NOTE: It is also possible to create new libraries or to save materials to a user library directly from the material applicator screen (that is, without having to use the material library manager).