RESONANCE
Every system has one or more natural frequencies where it “likes to vibrate.” If a system is excited by a small force at a natural frequency, it will exhibit very large magnitude of vibration. This wild vibration at the system natural frequency is known as resonance. A system is more likely to fail when it is in resonance due to the high internal forces imposed on the springs by the masses. The values of the natural frequencies of a system can be calculated if its masses, spring constants, and damping constants are known.
By applying a set of known forcing frequencies to the system, the natural frequency can be measured by determining the frequencies at which the system exhibits large magnitudes of vibration (a two-channel real-time spectrum analyzer is usually used to obtain these measurements).
The natural frequencies of the machine-support-piping system should be determined when one is analyzing the vibration of a machine. This is necessary to ensure that the forcing frequencies are not near the natural frequencies.
