Modal analysis is one of the main tools for investigating the dynamics of structures. In this method, the complex behavior of structures is expressed using the natural modes of the structure, which include natural frequency, mode shape and damping coefficient. Therefore, modal analysis is used to extract the modal model of a structure. Then, using this model, you can design, diagnose and analyze the structures.

Modal analysis can be used in many industries including automotive, aerospace, rail transportation, household products, oil, gas and petrochemical, and cement. Some of the applications of this method are as follows:

• Troubleshooting: finding resonance frequencies and trying to move the frequency of the working forces away from them
• Validation of finite element models
• Modifying the dynamics of structures using the extracted modal model and investigating the effect of structural changes on the performance of the structure
• Predicting the response of the structure due to the forces applied to it using the extracted model
• Obtaining the forces entered into the structure by solving the inverse problem with the modal model and the response of the structure
• Active control of vibrations: using the modal model to design controllers and observers

Experimental Modal Analysis (EMA) and Operational Modal Analysis (OMA) include two stages of testing and extracting data, and analyzing and obtaining mathematical models using the obtained data. Equipment such as hammer, electromagnetic shaker, accelerometer and force sensor are required for testing. The difference between EMA and OMA is that OMA does not measure input and applied forces to the structure. Usually, for large structures where it is not possible to stimulate the structure, the natural forces that enter the structure during operation are used as stimulation.