Finite element simulation of guided wave propagation in tendons

Guided wave ultrasonics is a promising technique for inspection and monitoring in many engineering fields. This Master’s thesis begins with a brief introduction to the physics of guided waves, followed by their application to the inspection of bars and tendons. Multi-wire tendons are widely used in prestressed, post-tensioned concrete structures, where the main problem is tendon corrosion caused by improper grouting. Because prestressing tendons carry very high stresses, a defect in a steel tendon can lead to sudden collapse without warning. At present, no reliable and simple non-destructive technique exists to detect such defects. Ultrasonic guided wave inspection offers the potential to identify defects and assess prestress levels over long ranges, in a non-destructive and continuous manner. The practical part of this thesis involves the development of a MATLAB code that generates input files for the wave propagation modelling software POGO. Using this code, it is possible to create meshes for rods or 7-wire tendons, and to simulate defects as well as the presence of transducers. This tool may serve as a valuable resource for future research in this field.