Application of modal assurance criterion on metallic and composite structures

The article presents the use of the Modal Assurance Criterion (MAC) for the purpose of spatially comparing mode shapes to identify differences in the degrees of freedom between test and analysis modes. In modal analysis, direct use of experimental results may include errors due to measurements limitations, for example modes duplications. Most popular applications of modal testing provide direct comparisons of deformed modal shapes between analytical and experimental findings. The responses of modal testing are measured at a number of sensors, which allow visualization of the measured motion. Before performing any operation to assess the quality of the analytical model, it is paramount that a correspondence be established between the analytical and experimental methods. The MAC methodology was evaluated on simple metallic beams, plates and sandwich-composite panels. MAC was verified on real measured data, which lead to the necessity of this algorithm for real life applications especially for sandwich-composite structures.