The beam (bar or rod ) is the most common element in SAM. It connects 2 nodes in a linkage mechanism, and it transduces force and torque. The end nodes may be fixed to world as an axis or act as a gliding node. At the end nodes angular fixation to other elements can be added. This demo also demonstrates the use of the beam as a linear actuator or a hydraulic cylindre. Therefore elongation is added to the beam.