(SLT 14)

Every mechanical system has a series of natural frequencies, each of which has its own damping characteristics. The natural frequency/frequencies will lie “dominant” in a system until they are excited by some external influence or forcing function. The vibration can be greatly amplified if a forcing function, such as unbalance, misalignment or a blade pass frequency happens to be within the range of a natural frequency. When such forcing frequencies coincide with or nearer to a natural frequency this phenomenon is known as "Resonance". This SLT covers the "Analysis of resonance and Critical speed problems".