Let us consider the motion of a SDOFsystem with which a dynamic vibration absorber (in the form of a lumped mass and a spring with complex stiffness) is attached. The complete system is shown in figures 18.1 and 18.2. with two variations of the same system.

The first case

Figure 18.1: Dynamic vibration absorber

The primary system here is subjected to base excitation

The second case

Figure 18.2: Dynamic vibration absorber

The primary system is directly excited, here

In both the cases, the excitations are purely harmonic in nature.