ABSTRACT
When a system is subjected to harmonic excitation, it is forced to vibrate at the same frequency as that of the excitation. Common sources of harmonic excitation are unbalance in rotating machines, forces produced by reciprocating machines, and the motion of the machine itself. These excitations may be undesirable for equipment whose operation may be disturbed or for the safety of the structure if large vibration amplitudes develop. Resonance is to be avoided in most cases, and to prevent large amplitudes from developing, dampers and absorbers are often used. Discussion of their behavior is of importance for their intelligent use. This chapter presents the theory of vibration-measuring instruments as a tool for vibration analysis. Vibratory forces generated by machines and other causes are often unavoidable; however, their effects on a dynamical system can be minimized by proper isolator design.
