基于压电智能骨料的微粒混凝土板裂缝监测研究OA

Based on the wave propagation method,the sensing performance and maximum damage identification depth of piezoelectric smart aggregates in crack monitoring of micro-concrete slabs are investigated.Five micro-concrete slabs are designed with different pro-tective layer distance L(the distance between the center of the piezoelectric smart aggregates and the right edge of the slab),and two smart aggregates are embedded in the slabs as actuator and sensor,respectively.A sinusoidal swept frequency signal of 1 kHz～5 kHz is used as the driving signal,the damage of the specimens is simulated through the cut crack,and the sensing signals are subjected to the time-frequency and wavelet-packet analyses.The results show that the time-domain signal amplitude,the frequency-domain signal power spectral density and the damage index I based on wavelet packet analysis are very sensitive to the crack damage of the micro-concrete structure,and the damage extent of the structure can be understood by observing the trend of these three indexes.The protection layer distance L affects the sensitivity of the piezoelectric sensors in receiving the damage signals of the micro-concrete.Finally,the formula for calculating the maximum damage identification depth is fitted according to the experimental results,which provides a reference for the optimal deployment of the piezoelectric sensors.