Patent ID: 9316620
Filing Date: 2016-04-19
CPC Classification: G01N

Claim Text:
1. A structural damage detection method for detecting damage of a structure, comprising: scanning along a structure surface with a tapper, wherein the tapper taps with a tapping force at a predetermined frequency band while scanning; measuring tapping response signals transmitted from the structure surface to the tapper at positions of the structure surface by a sensor, wherein the tapping response signals measured by the sensor comprises at least one of displacement, velocity, and acceleration; transforming the tapping response signals measured by the sensor to acquire a signal spectrum at each of the positions of the structure surface; intercepting from the signal spectrum a spectrum envelope corresponding to the predetermined frequency band of the tapping force; calculating a damage indicated value at the position of the structure surface, said calculated damage indicated value reflecting a degree of similarity between the spectrum envelope at each of the positions and the spectrum envelope at other positions; and determining a position where the damage indicated value changes abruptly as a position of structural damage; wherein calculating the damage indicated value at each of the positions of the structure surface comprises: generating a spectrum vector corresponding to the spectrum envelope at each of the positions, wherein each component of the spectrum vector comprises the spectrum value corresponding to a certain frequency in the spectrum envelope; calculating a damage indicated value to reflect the degree of similarity between the spectrum vector at one position, represented by i, and the spectrum vector at other positions, represented by j, comprises: calculating the damage indicated value as: where Y i and Y j are the spectrum vectors at said one position and at other positions in the structure respectively, a calculator • is an inner product calculation of the spectrum vector, |Y i | and |Y j | are lengths of the vectors Y i and Y j , and n is the number of the measured positions in the structure.