An Ultrasonic Guided Wave Inspection System for Hard To Access Civil Structures

Open Access
Author:
Advani, Siddharth Kishin
Graduate Program:
Electrical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 23, 2009
Committee Members:
  • Dr Joseph Rose, Thesis Advisor
  • Dr Qiming Zhang, Thesis Advisor
Keywords:
  • guided waves
  • transducers
  • non-destructive evaluation
  • ultrasonics
Abstract:
An ultrasonic guided wave inspection method is developed for the non-destructive evaluation (NDE) of hard to access isotropic plate-like structures. Experiments using Lamb waves and Shear Horizontal (SH) waves are conducted to determine the type of wave that will give maximum penetration power. Lamb waves are excited with an angle-wedge transducer and SH waves are generated using Electromagnetic Acoustic Transducers (EMATS). Results from these experiments are used to select the appropriate transducer at the correct operating frequency. Various tests are then carried out on buried plate-like structures having different anomaly geometries. Another significant objective of this work is to demonstrate the effectiveness of using wave propagation finite element methods to interrogate the possibility of estimating thinning loss due to corrosion in plates. A parametric study is carried out on two dimensional corrosion type surface breaking defects using Lamb waves. Based on this study, a method to solve the inverse problem of estimating the average thickness of an area being inspected is suggested.