動ひずみ測定を用いた振動入力の同定精度向上に関する研究

Abstract

Transfer Path Analysis (TPA) has been conducted in order to improve the noise and vibration quality of mechanical structures. However, the force identification in the TPA is still challenging problem and its accuracy has to be improved. The Matrix Inversion Method and the Apparent-Mass Matrix Method are approaches for force identification. The Matrix Inversion Method estimates the excitation force by the product of an inverse matrix of accelerance and a vector of actual operational acceleration. It is known that the Matrix Inversion Method is very sensitive to measurement noise especially at the resonance. Apparent-Mass Matrix Method has been recently proposed, which provides more accurate results than the Matrix Inversion Method. However, these methods are still insufficient in accuracy, and improvement of identification accuracy is required. This paper proposes a new force identification method by using strain measurement. The method estimates the force using the Strain Frequency Response Function (SFRF) instead of acceleration or Apparent-Mass Matrix. The SFRFs are more strongly affected by higher-order modes than accelerance FRF. Therefore, we considered that more accurate force identification can be obtained by using SFRF than the conventional method. A numerical simulation and a vibration experiment are conducted to compare the results by the proposed method with the conventional method.