| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for detecting a signal caused by a fracture of a tension material in prestressed concrete by surely separating it from noise signals caused by the traveling of a vehicle. SOLUTION: Energy of a received signal is integrated in a time space by 4 msec from the time point of signal generation to find total energy E500 while energy of the same signal is integrated in the time space by 1 msec from the time point of the signal generation to find partial energy Q1 of a headmost portion, finding a ratio Q1/E500. A signal having a ratio larger than a prescribed value is determined to be a heavily attenuated signal, that is, a noise signal, since its headmost portion has a high energy ratio. When the ratio is smaller than the prescribed value, following partial energy Q2 is found by integrating the energy of the signal from 1 msec after the time point of the signal generation to 2 msec thereafter. When a ratio Q2/E500 found by dividing the partial energy Q2 by the total energy E500 is in a prescribed zone, it is determined that the signal is caused by a fracture of the tension material; otherwise the signal is determined to be noise. COPYRIGHT: (C)2006,JPO&NCIPI |
