Frequency comb spectroscopy for reliable evaluation of vibration characteristics of nuclear facilities by means of ACROSS, 3; Data processing method to estimate the vibration characteristics in multi-scales by means of SOMPI method

Nishida, Akemi  ; Suzuki, Yoshio   ; Hayashi, Sachiko; Kunitomo, Takahiro*; Kumazawa, Mineo*; Hasada, Yoko*

The transfer function data in frequency domain acquired by ACROSS is analyzed by SOMPI method, which is based essentially on AR model as a discrete equivalent of linear dynamic system. The analysis is made in two steps, time domain analysis and space-wave number domain both in a consistent way as a linear dynamic system. We have derived an accurate set of vibration characteristics including attenuation and also the local characteristics such as wave propagation within the structural units and their interactions. Detection of small change in the structure is demonstrated by introduction of very precise measurement by ACROSS combined with the data analysis by SOMPI method.