Identification of characteristic parameters of layered structures by assuming the shape of the characteristic matrix

In this study, we present a novel method for determining key parameters essential for evaluating the health of layered structures. Our approach involves pre-assuming the shape of the characteristic matrix of the objects and determining the values of its elements from the frequency response function (FRF). By breaking down the FRF into real and imaginary components, which arise owing to damping effects, all parameters of the equations of motion can be treated as real numbers. We used a three-layered structure and conducted numerical simulations to validate the effectiveness of our proposed method. The results demonstrated the importance of using a damping model that accurately reflects the true damping characteristics, with general viscous damping proving to be the most appropriate assumption for parameter identification. Furthermore, we validated the applicability of our proposed method using experimental data measured from physical equipment. Our findings revealed that using experimental data with minimal measurement noise across a broad frequency spectrum resulted in consistent identification values and reasonable outcomes. However, there may be cases where the resonant peak frequency in the experimental FRF and the reconstructed FRF do not match perfectly. In such scenarios, we recommend modifying the characteristic parameters based on sensitivity analysis to achieve more accurate results.