Friction Overview
Friction is a resistive force that occurs in joints and between parts
in contact. When parts are in contact, friction is calculated based on
the static and dynamic coefficients of friction and the normal force acting
on the part. Mate friction is more complex because the size of the contact
area can affect the magnitude of friction.
Mate Friction
You can specify joint friction on the Analysis
tab of the Mate PropertyManager.
It is a resistive, sliding, surface force between parts that must be overcome
for the parts to move with respect to one another. The force develops
due to contact between the surfaces and the loads acting on the connection.
Joint friction takes into account standard friction between bodies as
well as aspects of joint geometry in determining the net frictional forces
acting.
The SolidWorks Motion mate friction model uses a combination of dimensional
information and a coefficient of friction. You can enter the coefficient
of friction directly, or you can have SolidWorks Motion calculate it based
on your choice of materials.
Mate friction is modeled as Coulomb friction
and only represents the dynamic friction in the joint.
Contact Friction
You can assign contact friction (friction that occurs between bodies
in contact) in the Contact
PropertyManager. The velocities and coefficients of friction used
are assigned automatically, based on the materials you define for each
contact set. However, they may not be the most appropriate parameters
based on the dynamics of the model. You can set these coefficients manually,
if necessary.
SolidWorks Motion uses the Coulomb friction method and fits a smooth
curve to the friction parameters to solve for the friction force).
For this example, the default friction parameters for dry steel in contact
with dry steel are used.
Dynamic Friction Transition Velocity: 10.16 mm/s
Dynamic Friction Coefficient: 0.25
Static Friction Transition Velocity: 0.1 mm/s
Static Friction Coefficient: 0.30
Frictional Force |
Static |
|
Dynamic |
Force (N)
|
|
Velocity
(mm/sec) |
In the Coulomb friction method, friction forces are calculated based
on four constants:
Dynamic
Friction Velocity: The velocity at which dynamic friction becomes
constant.
Dynamic Friction Coefficient:
The constant used to calculate friction forces once the body is no longer
at rest.
Static
Friction Velocity: The velocity at
which transition occurs between a stationary component and a moving component.
Static Friction Coefficient:
The constant used to calculate the force necessary to overcome friction
when a body is at rest.
To edit the velocity and coefficient parameters,
clear Material in the
Contact
PropertyManager.
Related Topics
Contact PropertyManager
-Friction