Assign Materials

By default, when you initially define your model boundaries, the properties of the first material in the Define Material Properties dialog will automatically be assigned to all regions of the model. However, in general it will be necessary for the user to:

• Assign the desired material properties to the different material regions of your model.
• Assign the staging sequence of the excavation(s).

There are two ways in which the assigning of material properties and excavation staging can be achieved:

1. Assign Properties dialog - the Assign Properties dialog, available in the toolbar or the Properties menu, can be used to assign material properties and excavation staging.
2. Right-click shortcut - assigning properties can also be achieved with a convenient right-click shortcut. If you right-click within any material zone of the model, the popup menu will provide shortcuts to assign material properties and excavation.

Assignment of material properties

To assign material properties with the Assign Properties dialog:

1. Select the Materials & Staging workflow tab.
2. Select Assign Properties from the toolbar or the Properties menu.
3. Make sure that Materials is selected in the drop-list at the top of the Assign Properties dialog.
4. If your model is multi-stage, in most cases material properties should be assigned at the first stage, therefore make sure that the Stage 1 tab is selected. (See below for more information about staged material property assignment).
5. In the dialog, select a material you would like to assign.
6. As you move the cursor over the model, notice that a cross-hair appears at the end of the cursor arrow. This indicates that you are in the mode to assign materials.
7. Place the cross-hair cursor inside a material zone in your model, and click the left mouse button. You will see that all finite elements in the zone will change to the colour of the assigned material.
8. To assign the same material to other zones of the model, repeat Step 7 as necessary. You may need to zoom or pan the view, in order to accurately select regions to assign. Note: you can simultaneously assign properties to multiple regions by clicking and dragging a selection window around the regions.
9. If your model has multiple material types, repeat steps 5 to 8 to assign the desired materials to all the zones of the model.
10. When you are finished with the Assign dialog, you can close it by selecting the X in the dialog, or by pressing Escape twice (once to exit the Assign mode and once to close the dialog).

Note: A material "zone" is any closed region defined by the intersection of any of the model boundaries (i.e. Excavation, External, Material, Stage or Joint boundaries). If a region is not "closed" you will discover this when you are assigning materials (the assignment will "leak" around the edges of any boundaries which do not intersect. If this occurs, you will have to reset the mesh, and edit the necessary boundaries, so that they intersect).

Assignment of Excavation

To assign excavation with the Assign Properties dialog:

1. In the Assign Properties dialog, make sure that Materials is selected in the drop-list at the top of the dialog.
2. Select the Excavate button in the Assign dialog.
3. Make sure the stage you are viewing is the stage at which you want to excavate. Use the Stage Tabs to view the desired stage.
4. Click inside the region you want to excavate. The finite elements and material colour will be removed, indicating that the region is excavated.
5. Repeat steps 3 and 4 to excavate your model in the desired sequence.

Note: any closed region of the model formed by the intersection of any of the model boundaries, can be excavated. In early versions of the program (prior to version 5), only the material within Excavation boundaries could be excavated. This restriction has been removed. For example, closed regions formed by the intersection of Stage boundaries and the External boundary, can be excavated.

Staged Assignment of Material Properties

In most cases, when materials are assigned to a multi-stage model, the assignment is applied at Stage 1, and the material type (for a given region) remains the same for all stages.

However, RS2 allows material properties to be assigned at any stage. This allows you to change material properties at different stages. This can be used for various purposes, for example:

• the assigning of a backfill material after a region has been excavated
• to model a change of material properties with staging (e.g. to simulate changes in material stiffness or strength).

When you assign material properties to a multi-stage model, it is important to understand how the assignment is applied by RS2:

• The material assignment is applied to the currently viewed stage and (by default) automatically propagated to all subsequent stages.
• The material assignment does NOT apply to stages BEFORE the current stage (i.e. the material type will remain unchanged in earlier stages).

Some examples of staged assignment of material properties are given below.

To assign backfill

You can backfill an excavated region by assigning another material to the region at any stage after the excavated stage – you will see that the finite elements and material colour reappear in the excavated region.

In the case of backfill, the number of times that a region would typically be assigned properties is THREE – the initial material assignment, the excavated assignment, and a final material assignment, representing backfill.

To change material properties

In the most general case, you can assign a succession of different material types at different stages, to a given region. This can be used to simulate changes in material stiffness, strength or other properties, with staging.

In this case, you must remember to assign materials starting with earlier stages and progressing to later stages, since a given material assignment will propagate from the current stage to all later stages (unless you use the This Stage Only option, see below).

Assign to current stage only

In some cases, you may wish to assign a material type to a given stage, without propagating the assignment to subsequent stages. For this purpose, you can select the This Stage Only check box in the Assign Properties dialog.

If you select the This Stage Only check box, and then assign a material type, the material assignment will only apply to the currently selected stage, and will NOT propagate to subsequent stages.

Right-Click Shortcut

To assign material properties or excavation using the right-click shortcut:

1. Select the desired Stage tab.
2. Right-click the mouse within a material zone of the model.
3. You will see a popup menu with an Assign Material sub-menu. From the Assign Material sub-menu, you can:
4. • excavate the region in which you clicked by selecting the Excavate option.
   • assign a material type to the region by selecting from the available list of materials (only the first 10 material types are available).

Make your selection and the excavation or material assignment will be applied at the selected stage.

5. If the material you wish to assign is not in the sub-menu, you can select More Properties from the sub-menu. This will display the Assign Properties dialog from which any available material type can be selected and assigned.

NOTE: not all material assignment options are available through the right-click. For example, the This Stage Only option (see above), requires the use of the Assign Properties dialog. Also, assigning multiple regions simultaneously with a selection window requires the use of the Assign Properties dialog.