Propagation Characteristics Experimental Study Of Acoustic Wave In Wave Guide Rod

As a dynamic examination technology, acoustic emission inspection can not only effectively examine the developing acoustic emission sources in the materials caused by such as crack spread, fibres rupture and other damnification, but also can monitor two times acoustic emission sources caused by leakage or others. In industrial production process, when pressure vessels and pipelines are inspected by acoustic emission technique, it is difficult to directly stick the sensors onto the surface of the object being examined if there exist such situations as high temperature, deep cold, radicalization, buries etc. Therefore, it is of vital significance to apply wave guide rod as assistant tool in acoustic emission inspection under the special operating condition.Based on the diffusing theory of wave guide rod, under the laboratory condition, the structure pattern of wave guide rod, the influence of different mediums where wave guide rod locates to the acoustic emission inspection and acoustic emission inspection to pipeline leakage using wave guide rod are all included in the paper. The research results provide the experiment gist to the application of wave guide rod in acoustic emission inspection. The contents of the paper are listed as follows:1. Theoretically analyze the diffusing rule of transient state elastic wave in wave guide rod, establish the amplitude mathematical expression of acoustic emission elastic wave diffusing in the wave guide rod;2. Carry experimental research on wave guide rods with three different lengths and seven different diameters. The findings show that the structure of wave guide rods has certain influence on AE waveforms and spectrums when the waves are excited by point sound sources, but for continuous sources, the influence is little;3. Carry experimental research on diffusing rule of wave guide rods in the water, the oil, the soil and analyze the amplitude of AE signals to study diffusing characteristic in different mediums;4. Establish acoustic emission experiment system of examining gas leakage in pipeline using wave guide rod as assistant tool, investigate AE inspection method to examine the gas leakage in pipeline with wave guide rod, finally discuss the characteristic of AE signals under different pressure and different diameter of leaking aperture.