Ultrasonics and NDE Group

Investigation of ultrasonic feature guided waves

It has been found that ultrasonic waves can be guided by features on the plate, such as welds, stiffener, bends, etc, with the energy retaining around the feature. This is an attractive finding, and can be applied as a screening tool to quickly inspect for defects such around the feature. Applications have been investigated in welded plate, bonded stiffeners and composite bends.

Selected publications (full publication list)

X. Yu, P. Zuo, J. Xiao, Z. Fan, Mechanical Systems and Signal Processing, 2019, 176-192, 2019.

X. Yu, M. Ratassepp, Z. Fan, Composite Science and Technology, 2017, 141, 120-129.

X. Yu, M. Ratassepp, P. Rajagopal, Z. Fan. Ultrasonics, 2016, 72, 95-105.

X. Yu, P. Manogharan, Z. Fan, P. Rajagopal, Ultrasonics, 2016, 65, 370-379.

Quantitative thickness mapping using ultrasonic guided wave tomography

Conventional ultrasonic thickness-gauging methods to inspect corrosion damage are tedious and expensive. We have developed a guided wave tomography algorithm based on full waveform inversion (FWI) to map the corrosion damage from remote locations. It uses the dispersion characteristics of guided waves, and reconstructs the thickness map by the inversion of ultrasonic signals captured by a transducer array around the inspection area.

Selected publications (full publication list)

J. Rao, M. Ratassepp, Z. Fan. IEEE Transactions Ultrasonics, Ferroelectrics, and Frequency Control, 2016, 63(5), 737-745.

J. Rao, M. Ratassepp, Z. Fan. Journal of Sound and Vibration, 2017, 400, 317 – 328.

J. Rao, M. Ratassepp, Z. Fan. Journal of Applied Physics, 2016, 120(19), 194902.

Simulation and modelling of NDT techniques

A number of numerical tools and methods have been developed to help with the design and validation of inspections. This includes:

• simulation of the propagation of ultrasound (linear and nonlinear) and its interaction with defects.
• modal study of waveguides with arbitrary cross-section for understanding properties of guided ultrasound in complex geometries.
• modelling material orientations in the anisotropic and inhomogeneous weld, and ultrasound propagation through such medium.

Selected publications (full publication list)

P. Zuo, X. Yu, Z. Fan, Journal of Sound and Vibration, 469, 115113, 2020.

P. Zuo, Z. Fan, Journal of Sound and Vibration, 406, 181-196, 2017.

P. Zuo, X. Yu, Z. Fan, NDT&E International 90, 11-13, 2017.

Acoustic metamaterial

We establish the fundamentals of the science of acoustic wave coupling for complex structures. Different from the traditional design of acoustic metalens, which suffers significant manufacturing challenges when the sound frequency is above 20 kHz (ultrasonic frequency), we propose a new approach to the design of acoustic metalens that can work well in the ultrasonic frequency range and significantly improve the resolution of ultrasonic imaging towards deep-subwavelength. This is achieved by introducing a new microscopic control wave theory to calculate the full wave dynamics in the metasurface. The coupled fields between the unit cells are quantified, and then utilized to control the diffraction pattern of them for wave manipulations.

Selected publications (full publication list)

J. Chen, J. Xiao, D. Lisevych, A. Shakouri, Z. Fan, Nature Communications 9, 4920, 2018.

J. Chen, J. Rao, D. Lisevych, Z. Fan, Applied Physics Letter, 114, 104101, 2019.

J. Chen, Z. Sun, Z. Fan, Applied Physics Letters 114 (25), 254102, 2019.