Every object in the nature has endless number of vibration frequencies and mode shapes that are called "Natural Frequencies". Calculation of these frequencies and their mode shapes are important to solve the vibration induced engineering problems. Natural frequencies and mode shapes of simple objects can be found by using analytical methods. However, complex shaped objects can only be analyzed by numerical methods. Finite element methods and the improved computer calculation capacities enable to investigate the natural frequencies and mode shapes of complex structures by idealizing them into computable small parts which are called "finite elements".

 Vibration analyses can be divided into two main parts. These are;

• Natural frequency and mode shape extraction
• Forced vibration analysis 

VES, accomplishes the uncertainties in the vibration analyses either by using other engineering tools or using own wide experiences.