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You can model an extrusion using the SimMechanics™ shape General Extrusion. Examples of extrusions include the I-beam and box-beam shapes. In this example, you model a simple solid with I-beam shape using the General Extrusion shape. For an example that shows you how to model a box beam, see Model Box Beam.
To represent the I-beam geometry, first identify its cross-section. This is the 2-D area that you sweep along an axis to obtain the 3-D I-beam. You can then specify the cross-section coordinates using the Solid block. The figure shows the I-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 I-beam, specify the coordinates so that the [0 0] coordinate is at the cross-section center. Because the I-beam cross-section is symmetric about the vertical axis, you need only define the coordinates for one cross-section half—e.g, the right half. You can then define the left half coordinates in terms of the right half coordinates.
By parameterizing the cross-section coordinates in terms of relevant I-beam dimensions, you can quickly change the I-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 I-beam.
Using the cross-section points that the figure shows, you define the coordinate matrix as:
right_half = [A; B; C; D; E; F]; xsection = [right_half; -right_half];
Add and connect the blocks to represent the I-beam. Include a Solver Configuration block so that you can visualize the solid in Mechanics Explorer during the modeling process.
Start a new model.
Add the following blocks to the model.
|Frames & Transforms||Reference Frame||1|
|Simscape™ Utilities||Solver Configuration||1|
Connect the blocks as they appear in the figure.
Double-click the Solid block and specify the following parameters.
|Geometry > Shape||Select General Extrusion|
|Geometry > Cross-Section||Enter xsection. Select units of in.|
|Geometry > Length||Enter L. Select units of in|
|Graphic > Visual Properties > Color||Enter rgb|
Right-click the Solid block and select Create Subsystem from Selection.
In the subsystem mask, initialize the solid parameters. Then, in the subsystem dialog box, specify their values.
Click the Subsystem block and press Ctrl+M to create a subsystem mask.
In the Parameters & Dialog tab of the Mask Editor, drag edit boxes inside the Parameters group and specify the following parameters.
In the Initialization tab of the Mask Editor, enter the initialization code for the xsection variable and click OK:
d = h/2-t; right_half = [w/2, -h/2; w/2, -d; t/2, -d; t/2, d; w/2, d; w/2, h/2]; xsection = [right_half; -right_half];
In the Subsystem block dialog box, specify these parameters.
|Color||[0.85 0.45 0]|
You can now visualize the I-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 I-beam geometry. To do this, in the subsystem dialog box, change the dimension parameter values. Then, update the model. The figure shows some examples.