Abstract
The experimental modal analysis is a technique for identifying modal parameters from vibration tests of mechanical structures. The single-degree-of-freedom (SDOF) methods using the frequency response function (FRF) is widely used in the actual application for identifying the modal parameters because of its simple operation. It is noted that the conventional SDOF method can be only applied when the target mode is dominant. But in some cases, the effect of the non-target mode can’t be ignored. In such cases, the multi-degree-of-freedom methods are used, while it is more effective if the modal parameters can be easily identified by the SDOF method. In this study, we propose a new SDOF method for identifying the modal parameters even though the vibration modes are relatively close. First, the theory of identification by the linear fit method in the case of approximating non-target mode components as a polynomial is explained. Next, the behavior of mode components close to the target mode is shown using the FRF of the cylindrical shell. Finally, we compare the modal characteristics identified using the conventional method and the proposal method, and conclude that the identification accuracy can be improved by the proposal method.
