Why do we calculate natural frequency of crankshafts?
The only reason I can think of, is that rotating crankshafts have a natural resonant frequency at which vibration would be the highest. I suspect they do so to ensure that the natural resonant frequency of the rotating crankshaft doesn’t coincide with the RPM’s required to cause a car to do the accepted speed limits. For example, you don’t want the resonant frequency of the crankshaft to coincide with the RPM’s required for an engine to drive a car at 55 MPH, as it would quickly destroy valve stems because of the stress caused by long-term exposure to this vibration. That’s my guess……..
