Rod
Massless flexible rod
Description
Connections
Parameters
Equations
Examples
The Rod component models a massless flexible rod. Rod can be seen as a spring/damper connection between two end frames with a given unstretched length and spring/damping constants.
Name
Modelica ID
Frame on one end of the rod
frame_a
Frame on the other end of the rod
frame_b
Default
Units
Unstretched length of the rod
L0
Spring constant
Kspring
Damping constant
Kdamper
Show visualization
true
True means the disk geometry is visible in the 3-D playback
visualization
0.01
Rod radius used for visualization only
r
Color
Rod color in the 3-D playback
color
Transparent
false
True means the geometry is transparent in the 3-D playback
transparent
Assuming that the translation vector, , is directed from frame_a, to frame_b, , the resultant forces of the rod are
where denotes unit vectors and and are the reaction forces applied to frame_a and frame_b, respectively, and
where is the instantaneous rod length. Note that in these equations, bold non-italic symbols denote vectors. Figure 1 shows the rod and the end frames.
Figure 1: Rod and end frames
Pendulum
You can use the Rod component, as shown in Figure 2, to model a pendulum with flexible connecting rod, swinging in 3-D space. You may want to define a specific initial condition for the end mass as well as the spring and damping constants of the Rod. Two visualization components are used to enhance the 3-D playback.
Figure 2: Model layout
Figure 3: 3-D playback snapshot
Slider-Crank Mechanism
In this example, a Rod, a Disk, and two Cylinders components are connected to revolute and prismatic joints, as shown in Figure 4, to model a slider-crank mechanism. This model is similar to the one discussed in the Linkage and Box help pages with the difference of using a Rod component to connect the crank to the slider.
Figure 4: Model layout
Figure 5: 3-D playback snapshot
See Also
Machine Elements
Multibody
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