Theoretical and experimental study of nonclassical nonlinear acoustic phenomena in concrete

摘要

In this paper, the propagation of sound wave and the nonclassical nonlinear acoustic properties in concrete were studied theoretically and experimentally. The results show that the resonance frequency shifts with the increase of the amplitude of accelerometer and the amplitude of the third harmonics is proportional to the square of the amplitude of accelerometer at fundamental frequency, which are the properties of nonclassical nonlinear acoustics. The values of the nonlinearity parameters were determined from the dependences of the resonance frequency shift and higher harmonic amplitude on accelerometer amplitude at fundamental frequency. The experimental results show that the values of the nonlinearity parameter change with the quantity of the water content in concrete, which are qualitatively explained in this paper.