Effects Of The Change Of Material Properties On Propagation Characteristics Of Ultrasonic Guided Waves Along The Pipe

In this Paper, firstly, some main studies and progresses in the field about crack detection in pipe using ultrasonic guided waves were reviewed, the basics of Ultrasonic Guided Wave was described. Secondly, based on the former theoretical examination, the dispersion equation of cylindrical and circumferential guided wave was obtained and calculated. And different guided wave modes in hollow circular cylinder were analyzed. Then excitation method in hollow cylinder was given and also the usual testing modes L(0,2) and T(0,1) excitation. Finally, using software Matlab and case study, given respectively-5%,0%and+5% changes in material properties including elastic modulus, Poisson's ratio and density, given the combination of different changes, the impact of value relations on the material properties of longitude mode L(0,2) and torsional mode T(0,m)(m=1,2) was studied. The relationship between the change of the material properties and phase velocity and group velocity about longitude mode L(0,2) and torsional mode T(0,m) (m=1,2) was obtained. And the sensitivity of the frequency dispersion curve of the material properties was discussed.