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本文利用剪切振动的超声换能器作发射声源和接收器,在实验室内观测横波在已知弹性结构的人工复合材料和裂隙细砂岩样品中的传播特征。由实验证实:(1)横波浩复合材料层面或岩样裂隙方向传播时,存在两种速度的横波:其中快横波的偏振方向平行样品的弹性结构方向(层面或走向裂隙),而慢横渡的偏振方向垂直结构方向。(2)当入射横渡(发射器或接收器)偏振方向与样品弹性结构方向平行或垂直时,只能观测到一种横渡(快或慢横波),而在其它方位可同时观测到快、慢横波。快、慢横波的相位与发、收换能器的偏振性能有关,振幅可用方位角或偏振角的三角函数未表示。(3)比较两种样品的弹性结构特征发现,它们具有相同的速度各向异性,但快、慢横波的衰减特性不同。这表明各向异性介质的弹性结构方向控制着速度各向异性,而结构特征影响横波的衰减各向异性。
In this paper, shear vibration ultrasonic transducer is used as the emission sound source and receiver to observe the propagation characteristics of transverse waves in artificial composite materials and fissured fine sandstone samples with known elastic structures in the laboratory. The experimental results show that: (1) There are two kinds of shear waves in the shear wave propagation direction of the shear wave composite layer or rock specimen: the fast direction of the fast shear wave is parallel to the elastic structure direction (layer or fracture) of the sample, Polarization direction Vertical structure direction. (2) Only one kind of crossover (fast or slow shear wave) can be observed when the incident cross (transmitter or receiver) polarization direction is parallel or perpendicular to the direction of the sample elastic structure, while fast, slow Stroke. The phase of the fast and slow shear waves is related to the polarization performance of the transmitter and receiver, and the trigonometric function of the azimuth or polarization angle of the amplitude can not be expressed. (3) Comparing the elastic structure characteristics of the two samples, we found that they have the same velocity anisotropy, but the attenuation characteristics of fast and slow shear waves are different. This indicates that the direction of the elastic structure of the anisotropic medium controls the velocity anisotropy, and the structural characteristics affect the shear anisotropy of the transverse waves.