A NOVEL EFFICIENT APPROACH FOR DEFECT DETECTION IN PIPELINE STRUCTURES USING GUIDED ULTRASONIC WAVES

Detection of defects is a most important task in engineering subjects because a very tiny flaw in a structure might lead to a disaster at a later stage. In this paper, a novel, efficient and effective approach using guided ultrasonic waves for defect detection in pipeline structures is proposed. Based on boundary integral equations and Fourier transform of space-wavenumber domain, this developed method for quantitative detection of defects comprises three stages: first, theoretical foundation of quantitative detection is established using the boundary integral equations and the term in the integral is defined as B(k), k for wavenumber, according to Born approximation. Subsequently, B(k) of a known defect can be written as B-0(k) by Fourier transform of space-wavenumber domain to approximately represent the feature of an unknown defect in wavenumber domain. Finally, by combining B-0(k) and reflection coefficients C(k), the location and shape of the unknown defect can be efficiently and effectively reconstructed. Several examples have been tested to demonstrate the correctness of the proposed methodology. It is concluded that the general two-dimensional surface defects can be efficiently detected by this novel approach.