A 2D Numerical Model of Ultrasonic Wave Propagation in Wooden Utility Poles Using Embedded Waveguide Excitation Technique

Abstract

Embedded waveguide technique is often not considered as a method for introducing ultrasonic wave for nondestructive testing (NDT). Because of the unique surface condition of wooden utility poles, the rough and uneven surface between the medium and the sensor introduces variation and signal attenuation, which impedes the use of a contact-based ultrasonic sensor. Many inspection and utility firms have adopted the use of inserting a small nail into the wooden pole for NDT. The mechanisms of excitation and reception of ultrasonic wave, however, are very different from the traditional contact-based mounting technique. Because very little research has been carried out on this methodology, this study focuses on the understanding of embedded waveguide excitation and reception in the time domain for wooden structure assessment in cylindrical symmetry. The resulted time domain waveform response is analyzed, and the associated findings will help infer important structural condition for NDT assessments. The study consists of numerical and empirical results to validate and understand the waveform characteristics and the associated energy modes that exist (Bodig 1982) in the two-dimensional wave propagation in a boundary medium