Shafts (critical speed)
Subject
The most common method for transmitting power from one place to another is via a rotating shaft, and apart from a properly designed lubrication system and correct bearing selection (see Bearings (low friction) and Bearings (plain)) the difference between a good shaft and a bad shaft is surprisingly little. It is therefore very important to understand what makes this difference and how to accurately define its most important characteristics.
For example; responsiveness and performance can be severely reduced if it is overdesigned, and vibrations are responsible for power loss, excessive wear, noise, and early failure from fatigue all of which can be eliminated by ensuring that your shaft runs at the correct speed(s).
Calculator
Shafts calculates the performance characteristics of a rotating shaft identifying critical speed, natural frequency, amplification factor and stresses for four different end configurations.
The shafts calculator is a quick and simple calculation facility that may be used alone or in conjunction with our other related calculators; (Beams, Fatigue, Metals, Combined Stress, Bearings, Journals, Stress Concentration, Limits and Fits, Shock Loads, etc.) and its technical help should provide all the help you need to get the most out of it.
For help using this calculator see Technical Help
Shaft Calculator  Options
Shafts includes the following calculation options: Cantilever, SimpleSimple, SimpleFixed and fixedFixed all of which have the same input data as listed below.
You enter: 
and the shafts calculator will provide: 


Natural frequency

Frequency ratio

Critical speed

Radial force

Static deflection

Dynamic amplitude

Bending moment

Shear stress

Bending stress

Principal stress

Shaft spring constant

Amplification factor

Check minimum system requirements