過渡応答を利用した実構造物と有限要素モデルの乖離要因の特定法

抄録

In this paper, we propose a new approach to identify the error factor of frequency response function (FRF) between actual structure and finite element (FE) model. The model updating approach using sensitivity and optimization algorithm that have been conventionally applied for making it more accurately. Usually, the parametric design variable like thickness is adopted as updating variable which generates the calculation easier. However, the actual error factor is included in non-parametric. For that reason, its application is limited. Accessible concept which utilizing the driving point FRF that is often practiced in engineering. In this technique, a driving point FRF of each components in the assembled structure is compared in an actual structure and FE model to identify the error factors. Nevertheless, it is difficult to recognize it precisely. Since, the FRF is calculated from the time history which contains of reflection wave from the whole system, and the driving point FRF involves not only influence of excited element, yet whole system. Therefore, we propose a new approach using driving point transient response. When a certain segment is excited, its vibration propagates as a wave from excited segment to the whole system. However, driving point transient response which was immediately measured after excitation, includes only influence of excited segment. By comparing the driving point transient response from those main concern, it is possible to decide whether the excited segment is an error factor or not. In addition, to confirm its influence to the measured transient response, the mutual mean compliance in the time domain was employed. The driving point transient response were utilized on a simple beam structure to verify the proposed approach.