抄録
In this paper, we propose an identification flow of contributing factors to the difference of FRFs between a finite element model and an actual structure. Conventionally, to identify the factor of difference, a driving point FRF of the part in the assembled structure is compared in a FE-Model and an actual structure. But it is difficult to identify whether the part is factors of difference with accuracy, because the other parts also influence the driving point FRF. As the other conventional identification flow, there is a model-update method that update the model minimizing the difference of FRF by using the structural sensitivity. However, the model update-method cannot also identify the factor with accuracy. Because the model-update method just optimize a FE-Model. Therefore, we propose a boundary node constraint method which compares driving point FRFs between a FE-Model and an actual structure. By the constraint, driving point FRFs are independent of other parts, and accordingly those vibration characteristics have no influence of other parts. Using the nodal constraint method, it is possible to identify factors to the difference of FRFs in the joint part by selecting the constraint point. And it is possible to identify that factors of the difference of FRFs exist in mass or stiffness by comparing mass line or stiffness line of the FRFs. In this paper, the nodal constraint method is verified numerically by FE-Models simulating experimental FRFs.
