resonance is a frequency level of any rotating body or oscillating body, if normal frequency of any rotating body approaches towards the natural frequency of it's own it leads to rising of resonance . At this level maximum vibration occure in body(i.e. shaft) which leads to bending , twisting and damaging of body.
let wi is any normal frequency of any rotating body(i.e Shaft) and Wn be its natural frequency.
then , for satisfying resonance condition ,
- where Wn=(k/m)0.5
- w= rotating frequency (from X= xsinwt)