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You can model an extrusion with a hole. One example is the box beam. Specifying hollow cross-sections must satisfy the cross-section guidelines. See Cross-Section Coordinates. In this example, you specify the cross-section coordinates of a box beam. For an example that shows you how to model an I-beam extrusion, see Model I-Beam.
To represent the box beam geometry, first identify its cross-section. This is the 2-D area that you sweep along an axis to obtain the 3-D box beam. You can the specify the cross-section coordinates using the Solid block. The figure shows the box beam cross-section that you specify in this example.
The [0 0] coordinate identifies the solid reference frame origin. To place the reference frame at the center of the box beam, specify the coordinates so that the [0 0] coordinate is at the cross-section center. By parameterizing the cross-section coordinates in terms of relevant box beam dimensions, you can later change the box beam dimensions without having to reenter the cross-section coordinates. The figure shows the cross-section dimensions and coordinates that you must specify to represent the box beam.
Using the cross-section points that the figure shows, you define the coordinate matrix as:
OuterCS = [A, B, C, D, E]; InnerCS = [F, G, H, I, J]; CS = [OuterCS; InnerCS];
For more information about specifying the hollow cross-section coordinates, see Hollow Cross-Sections.
Add and connect the blocks to represent the box beam. Include a Solver Configuration block so that you can visualize the solid in Mechanics Explorer during the modeling process.
Drag these blocks into a new model.
|Simscape™ Utilities||Solver Configuration||1|
Connect the blocks as they appear in the figure.
In the Solid block, specify these parameters.
|Geometry > Shape||Select General Extrusion|
|Geometry > Cross-Section||Enter CS. Select units of cm.|
|Geometry > Length||Enter L. Select units of cm|
|Graphic > Visual Properties > Color||Enter RGB|
Select the Solid block and generate a subsystem, e.g., by pressing Ctrl+G.
In the subsystem mask, initialize the solid parameters. Then, in the subsystem dialog box, specify their values.
Select the Subsystem block and create a subsystem mask, e.g., by pressing Ctrl+M.
In the Parameters & Dialog tab of the Mask Editor, drag five edit boxes inside the Parameters group and specify these parameters.
In the Initialization tab of the Mask Editor, enter the initialization code for the xsection variable and click OK:
D1 = W/2-T; D2 = H/2-T; OuterCS = [-W/2,-H/2; W/2,-H/2; W/2,H/2; ... -W/2,H/2; -W/2,-H/2]; InnerCS = [-D1,-D2; -D1,D2; D1,D2; D1 -D2; -D1,-D2]; CS = [OuterCS; InnerCS];
In the Subsystem block dialog box, specify these parameters.
|Color [R G B]||[0.85 0.45 0]|
You can now visualize the box beam that you modeled. To do this, on the Simulink® menu bar, select Simulation > Update Diagram. Mechanics Explorer opens with a 3-D display of your model. Rotate, pan, and zoom to explore.
Try modifying the box beam geometry. To do this, in the subsystem dialog box, change the dimension parameter values. Then, update the model. The figure shows some examples.