压电陶瓷混凝土结构应力波衰减特性试验

Experimental Research on Stress Wave Attenuation Behavior of Concrete Structure with Piezoelectric Ceramic Sensors

目的研究不同频率下应力波在混凝土中传播的衰减特性.方法以压电陶瓷片为声源,选取一对压电陶瓷传感器并埋置在素混凝土梁内部,其中一个传感器用于信号发射,另一个用于信号接收.在输入信号幅值一定的情况下,通过改变信号主频来考察输出信号幅值的变化情况.结果压电陶瓷混凝土结构应力波的衰减主要与激振频率和幅值以及介质的性质有关,衰减系数同频率之间的关系近似符合三次多项式函数;频率-衰减系数曲线存在两个临界频率f1和f2.结论利用试验数据拟合出应力波在混凝土介质中传播时频率与衰减系数的关系曲线,并给出一定频率和幅值的应力波在混凝土介质中有效传播距离的计算方法,为合理选择压电陶瓷传感器间距的提供了依据.

Stress wave attenuation behavior in the concrete structure with different frequencies is researched in this paper.A pair of piezoelectric ceramic transducers are buried into a plane concrete beam while one is used as an actuator to transmit signals,the other is applied as a sensor to receive signal.With keeping amplitudes constant of input signals,the alterations of the amplitudes of the output signals were investigated by changing frequencies of input signals.Stress wave attenuation behavior in concrete structure is related to amplitude,frequency and characters of propagation medium.The relationship curve between the frequency and the attenuation coefficient is about cubic polynomial,and there are two critical frequencies f1 and f2 on the curve.As a result,the relationship curve between the frequency and the attenuation coefficient is fitted by test data.The calculation method for propagation distances of stress waves with constant amplitudes and frequencies in the concrete medium is proposed,and the results can provide an effective evidence for correctly placing transducers.