Practical Solutions to Machinery and Maintenance Vibration Problems
Chapter 2, Mechanical Resonance
Section 4, Why Some Machines do not Seem to Resonate as Often as Others
One more observation on this subject that is extremely important. The writer has, on rare occasions, found plants where excessive vibration due to a resonating part occurred infrequently. Machine after machine ran very smoothly with almost no vibration. The usual symptoms for resonance, such as modal shape curls or phase changes, were almost non-existent. In these rare situations, the source vibrations were reduced to very low values through exceptionally close precision balancing, precision alignment, compensations for thermal growth on all machines -- and not just some, very careful and knowledgeable assembly. Yes, in these machines, like all machines, certain parts had resonant frequencies that corresponded to source vibration frequencies. However, the source amplitude energy was not large enough to actually resonate the parts. Therefore, as plants learn how to improve all aspects of their machinery's running smoothness, the percentages given in the chart, should decrease drastically, and finally resonance magnification will become extremely rare.
This textbook contains only part of the information in our Practical Vibration Analysis seminar.