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You can model solids of revolution using the SimMechanics™ Revolution shape. Examples of solids of revolution include cone and circular dome shapes. In this example, you model a simple solid with cone shape using the Revolution shape. For an example that shows you how to model a circular dome solid, see Model Dome.
To represent the cone geometry, first identify its cross-section shape. This is the 2-D area that you can revolve about an axis to obtain the 3-D cone. Then, specify the cross-section coordinate using the Solid block. For more information, see Cross-Section Coordinates. The cone in this example has a trapezoidal cross-section. The figure shows this cross-section.
The [0 0] cross-section coordinate identifies the reference frame origin for this solid. To place the reference frame at the cone tip, specify the coordinates so that the [0 0] coordinate is at the tip. By parameterizing the cross-section coordinates in terms of the relevant cone dimensions, you can quickly change the cone dimensions without having to reenter the cross-section coordinates. The figure shows the cross-section dimensions and coordinates that you must enter to specify the cone.
Add and connect the blocks to represent the cone. 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.
In the dialog box, specify the following parameters.
|Geometry > Shape||Select Revolution|
|Geometry > Cross-Section||Enter xsection. Specify 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.
theta = atan(r/h); xsection = [0 0; r h; r-t/cos(theta) h; 0 t/sin(theta)];
In the Subsystem block dialog box, specify these parameters
|Color||[0.85 0.45 0]|
You can now visualize the cone 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 cone geometry. To do this, in the subsystem dialog box, change the dimension parameter values. Then, update the model. The figure shows some examples.