Beam flexural rigidity intelligent monitoring method based on bending wave transfer function

Abstract

The invention discloses an intelligent beam flexural rigidity monitoring method based on a bending wave transfer function, which comprises the following steps: connecting a piezoelectric sensor with a high-frequency signal acquisition instrument to acquire an elastic wave signal in a beam, and deriving two kinds of bending waves in the beam based on the bending wave transfer function, namely the transfer characteristics of a propagation wave and a near-field wave; according to the present invention, the wave velocities and the attenuation characteristics of the two bending waves are different, the wave velocity of the propagation wave is increased along with the increase of the section stiffness, the propagation characteristic is strong, and the wave velocity change rule of the near-field wave is complex and is easily attenuated, such that the vibration excitation device is arranged at the reasonable position, and the vibration excitation device is adopted to transversely impact the beam body and excite the bending waves so as to achieve the bending wave vibration excitation. The near-field wave interference is filtered by using the attenuation characteristic of the near-field wave, the wave velocity of the bending propagation wave is accurately identified by combining wavelet transform, the relational expression of the wave velocity and the section stiffness is deduced by using the bending wave transfer function, the real-time change of the section stiffness of the beam is obtained by inversion, and the evolutionary process of the bending stiffness of the beam is monitored in a lossless and real-time manner.

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