Definition of a Beam: A bar subjected to forces and couples that lie in a plane containing its longitudinal axis is called a beam.
The Forces will act perpendicular to the longitudinal axis of the bar.
Cantilever Beams :
If a beam is rigidly supported at only one end in such a manner that the beam cannot rotate at that point, it is called as cantilever beam.
The other end of the beam is free to deflect but from the end where it is fixed, it cannot rotate. The end which is fixed is said to be ” restrained.” The reaction of the beam at the fixed end consists of a vertical force and a couple acting in the plane of the applied loads.
Simple Beams :
A beam which is freely supported at both ends is known as simple beam.
The term “freely supported” implies that the end supports of the beam are capable of exerting forces on the beam not any moment. So in simple beams no “restrained” is offer to the angular rotation as the beam deflects under the loads.