COSMOSMotion supports the following types of contact:
Point-curve - Restricts a point on one rigid body to lie on a curve on a second rigid body.
Curve-curve - Constrains one curve to remain in contact with a second curve.
Intermittent curve-curve - Applies a force to prevent curves from penetrating each other. Only active if the parts are touching
3D Contact – Applies a force to prevent bodies from penetrating each other. Only active if the parts are touching
Only the first two types of contact impose degree-of-freedom restrictions on the connected parts and are true constraints.
The following table shows the contacts constraints in COSMOSMotion with the degrees of freedom that they constrain.
|
Constraint: |
Translational DOF: |
Rotational DOF: |
Total DOF |
|
Point-curve |
2 |
0 |
2 |
|
Curve-curve |
2 |
0 |
2 |
|
Curve-curve intermittent |
0 |
0 |
0 |
|
3D |
0 |
0 |
0 |
Intermittent contact is a COSMOSMotion feature that enables you to model situations where bodies collide, roll, and/or slide. The two forms of intermittent contact you can create are intermittent curve-curve contact and 3D contact.
Intermittent curve-curve contact is used when the parts or features that are touching, can be represented as profiles in a two-dimensional plane. ADAMS/Solver then monitors the position of these profiles, and, if they start to penetrate, applies forces to prevent this. Intermittent curve-curve contact is typically a faster solution than 3D contact. It is sometimes necessary, however, because of the surface contact points between bodies.
Contact is similar to an impact force in that the material properties of the parts are used to define the contact parameters. Conversely, contact differs from an impact force because any point along a curve or geometry is used in the contact. Contact also simulates friction forces between parts.
While
contacts are listed under the constraints branch of the IntelliMotion
Browser, they do not constrain any degrees of freedom in the motion model.
Intermittent curve-curve contacts and 3D contacts merely restrict penetration
between parts based on contact forces.