Testing of cracks on a cylindrical cavity by creeping waves

The dispersion equation of the creeping waves around a cylindrical cavity is solved by Newton iteration method,the dispersion and attenuation behaviors of creeping waves are analyzed accordingly.Dynamic photo-elastic technique is employed to show the intuitional image of creeping waves and based on which different types of scattering waves around a cylindrical cavity are analyzed.According to the characteristics of dispersive,attenuation and radiation of shear wave,a wedge-shaped pulse-echo experiment setup is designed to measure the shear waves radiated by creeping waves which are reflected by cracks in a certain position.The measured time difference between creeping wave signal and the reflection from the front surface of the cylinder agrees well with theoretical prediction.Further experiments show that the echo amplitude grows monotonously as the crack size increases and trends to be stable when the crack size is large enough.The above results provide a theoretical foundation as well as an implement method for quantitative testing of cracks on a cylindrical cavity by creeping waves.