Chapter 2 Review of Forces and Moments - Brown University

2D pinned joints are often represented as shown in the picture below
A
A
R Ax
R (1/2) Ay
R (1/2) Ax
A
(2)
R Ay
(1)
A
R (1/2) Ax
R (1/2) Ay
Roller and journal bearings
Bearings are used to support rotating shafts. You can buy
many different kinds of bearing, which constrain the shaft in
different ways. We’ll look at a couple of different ones.
Example 1: The bearing shown below is like a pin joint: it
allows rotation about one axis, but prevent rotation about the
other two, and prevents all relative displacement of the shaft.
Reaction forces: No relative motion is possible at this kind of
bearing. There must be 3 components of reaction force.
Reaction moments: Relative rotation is allowed about one axis
(parallel to the shaft), but prevented about the other two. There must be two components of reaction
moment.