Classification of the Extent of Wall Thinning in Pipes Based on Simulations in the Time and Frequency Domain

Numerical simulations created with Computer Simulation Technology (CST) modeling are used to classify and evaluate the microwave signal (waveform) in order to determine whether various parameters of pipe wall thinning (PWT) can be identified. Microwaves are used to carry out the measurement of PWT in 9 CST simulations using three cross-sectional profiles, three lengths of PWT, and three depths of PWT, to determine whether there are differences in waveforms that can be used to distinguish the parameters of unknown discontinuities (PWT). The modeled system uses the pipe as a circular waveguide (bandwidth 0.486GHz) with sweeping frequencies from 1.914GHz to 2.4GHz. Waveforms are found to be distinguishable based on the three parameters modeled in the study. This research establishes the possibility of creating a nondestructive testing system with which PWT discontinuities might be characterized using microwaves in the S₁₁ and S₂₁ scattering parametrics. The waveforms generated for known series of PWT cases, once cataloged, can be used in the future to identify discontinuities in test pipes, and to determine their degree of similarity to the standardized waveforms via pattern recognition algorithms.