You can use forces to model spring and damping elements, actuation and control forces, and many other part interactions. This section introduces forces and explains how to create them.
Forces define loads and compliances on parts. Forces do not absolutely prohibit or prescribe motion. Therefore, they do not add or remove degrees of freedom from your model. Forces may resist motion, such as springs or dampers, or they may induce motion.
COSMOSMotion provides the following type of forces:
Applied Forces - Applied forces are forces that define loads and compliances on parts so that they move in certain ways. Applied forces are very general, but you must supply your own description of the force behavior by specifying a constant force value or expression function. The applied forces in COSMOSMotion are the action-only force, action-only moment, action/reaction force, action/reaction moment, and impact force.
Flexible Connectors - Flexible connectors resist motion and are simpler and easier to use than applied forces because you only supply constant coefficients for the forces. The flexible connectors include translational springs, torsion springs, translational dampers, torsion dampers, and bushings. Learn more about springs, dampers, and bushings.
Gravity - For more information on gravity and setting gravity, see Gravity.
For every force that you create in COSMOSMotion, you specify the following information:
Whether the force is translational or rotational.
To which part or parts the force is applied.
At what point or points the force is applied.
Magnitude and direction of the force.
The following sections explain how to define the magnitude and direction of forces.
A force function specifies the force magnitude throughout your simulation. You can define force magnitudes in COSMOSMotion in the following ways:
Enter values used to define stiffness and damping coefficients (springs and dampers only). In this case, COSMOSMotion automatically makes the force magnitude proportional to the distance or velocity between two points. The coefficients represent the proportionality constants.
Select a predefined function from the pull-down list (Step, Harmonic, and Spline).
Enter an expression function using the Function Builder feature.
Enter an expression function directly into the Function Expression text box using the library of MSC.ADAMS functions.
You can define force directions in COSMOSMotion in one of two ways:
Along an axis defined by an edge or a plane.
Along the line-of-sight between two points.
The way you define the directions of your forces depends on which forces you are creating. If you are creating an action-only force, the force direction remains fixed with respect to some part in your model, either a moving part or the ground part. In this case, you can define the force direction using one vector defined by an edge or a plane.
If you are creating an action/reaction force, then the direction along which you want the force applied is defined by the line between two points in your model and is constantly changing throughout the simulation. In this case, you can define the force direction as the line between the two points.