Patent ID: 7634392
Filing Date: 2009-12-15
Classification: G01N

Abstract:
1. A method of using a computer system to model the magnetostrictive effect when a guided wave incident signal is reflected within a conduit having a defective region; comprising: modeling the defective region as having a succession of n layers along a length of the pipeline, each layer having a cross-sectional area that varies from the cross-sectional area of the pipeline; calculating a cross sectional area of each of the layers; calculating an impedance of each layer as the product of the density of the pipe material, the velocity of acoustic waves in the material, and the cross-sectional area of the layer; calculating an overall complex input impedance of the region; wherein the calculating step is performed by recursively calculating the input impedance of each two successive layers as: where Z calculating a reflection coefficient based on the overall input impedance and the input impedance of a conduit without defect; calculating a spectral amplitude of the incident signal; using the reflection coefficient as a transfer function of the spectral amplitude of the incident signal, thereby obtaining a frequency domain representation of the defect signal data; and storing the defect signal data in memory of the computer system.