【摘要】 为研究超声波在混凝土中的传播和衰减特征,建立基于细观结构的数值混凝土模型,利用黏弹性声波方程模拟超声波在混凝土中的传播。通过对不同参数模型的模拟,研究骨料、孔隙和钢筋对超声波衰减的影响。研究结果表明:混凝土中的孔隙虽然很小,但它们是引起超声波能量衰减的主要因素之一;混凝土的黏滞性是超声波能量衰减的另一个主要因素,它导致超声波能量随传播距离的增大呈指数衰减;钢筋和骨料对超声波能量衰减不大,但能引起复杂的反射和散射,增加空洞等异常波形识别的难度。更多还原

【Abstract】 In order to study the ultrasonic propagation and attenuation characteristics in concrete, numerical concrete models were established based on the microstructure, and the ultrasonic propagation in concrete was simulated by viscoelastic acoustic wave equation. Attenuation caused by aggregate pores and reinforce were studied through models of different parameters. The results show that attenuation of ultrasonic energy is mainly caused by pores and viscosity of concrete, though pores are small. Viscosity of concrete leads ultrasonic energy exponential decay with propagation. Steels and aggregates cause small attenuation of ultrasonic, but they can cause complex reflection and scatter, which makes it difficult to identify the waveform caused by voids and other anomalies.更多还原