A brief breakdown on how to perform a graphical velocity vector analysis on a 4 bar link mechanism

Velocity of various points on a mechanism can be analyzed analytically or graphically using vectors

Analyzing a mechanism graphically means defining the magnitude and direction of the velocity vectors.

Here is a walkthrough on how we can derive the Velocity diagram when solving graphically.

Consider a rigid body AB with two different velocities at two points A and B

The velocity difference vector will give the relative velocity of point B with respect to point A.

**Velocity analysis of coupler of 4 bar link mechanism**

Since links OA and BD are both rotating about fixed centers they will have linear velocities respectively at the instant as shown

**How to find absolute velocity of point C? **

Same way we found velocity difference for B with respect to A we can do the same for C with respect to A

Also we can find velocity difference for C with respect to B too

Creating the Velocity polygon and bringing all the vectors into one diagram

Categories: Mechanism and Machine design