Abstract

Guided Ultrasonic Waves (GUW) inspection is an important method of Non-Destructive Evaluation (NDE) used for the inspection of pipelines, storage tanks and pavements owing to their sensitivity and long range propagation. Nonlinear Ultrasonics (NLU) are used for the enhanced inspection of structures by increasing the sensitivity of measurements to detect micro cracks and defects. However, there could be a lot of false positives because apart from material based nonlinearity or micro-crack based nonlinearity, it could also arise from equipment electronics, nonlinearity due to transducer and couplant etc. To reduce the false positives and improve the detection of ultrasonic guided wave signals, here we propose a new technique of using a waveguide metamaterial rod by creating bandgap wherein wave propagation of higher harmonics is hindered. The proposed metamaterial waveguide demonstrates its capability of suppressing all higher harmonics experimentally. This will help to improve in the ultrasonic guided wave measurements more accurately as they are free of nonlinearities. The proposed waveguide metamaterial made of Aluminium consists of an array of baffles which are arranged periodically along the surface of the rod. This could help in improved ultrasonic measurements using waveguide sensors which find important application for like fluid rheological properties, flow and temperature.

How to Cite:

S R, S. K., V K, K. ., Balasubramaniam, K. . & Rajagopal, P. ., (2019) “Higher harmonics suppression using nonlinear waveguide metamaterial rod”, Review of Progress in Quantitative Nondestructive Evaluation .