A test study on the influence of geometric parameters of annular trench on vibration isolation area

Abstract

In order to study influences of geometric parameters such as depth, width, and distance of an annular trench on a vibration isolation area, an outdoor test of the annular trench was carried out, and the contour map of the amplitude reduction ratio was drawn. The area with the amplitude reduction ratio of not more than 0.35 was used as the evaluation index of the effective vibration isolation area, and the influence of the above geometric parameters on the effective vibration isolation area was analyzed. The results show that the depth of the trench, width of the trench, the distance from trench to the vibration source and center angle of the trench have different effects on the effective vibration isolation area. When the ratio of the trench depth to Rayleigh wave length is 0.54-0.77, the ratio of trench width to Rayleigh wave length is 0.23-0.33, and the ratio of the distance from the trench to the vibration source to Rayleigh wave length is 1.18-1.52, a good effective vibration isolation area of annular trench can be obtained. Under the conditions of this test, continuously increasing the ratio of each parameter is not beneficial to enlarge the effective vibration isolation area. The central angle of the annular trench is an important factor affecting the effective vibration isolation area. Increasing the angle can obviously enlarge the area of the effective vibration isolation area. When the angle is 90, a discontinuous effective isolation area will be formed in the isolation area. The selection of the angle is related to the frequency, when the effective isolation area of the same size is achieved, and the angle increases with the decrease of the frequency.