System analysis for structures by using acoustic frequency comb, 2; Accurate data measuring method; Rational data analysis method

Kumazawa, Mineo*; Kunitomo, Takahiro*; Nishida, Akemi  

ACROSS (Accurately Controlled, Routinely Operated, Signal System) is such a precise metrology of frequency response characteristics that the accurately controlled sinusoidal waves (acoustic comb) is used as an input to the linear dynamic system, and induced vibration as an output is measured by the accelerometers synchronized accurately to input. This technology has been developed to be used on a routine basis for the subsurface structural analysis and state-monitoring of the geological targets. We discuss the theoretical background and the related subjects of applying this method to the artificial structures. 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. 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.