Guided electromagnetic waves for damage detection and localization in metallic plates: numerical and experimental results

Abstract

Electromagnetic waves in the microwave and millimeter-wave frequency range are used in non-destructive testing and structural health monitoring applications to detect material defects such as delaminations, cracks, or inclusions. This work presents a sensing concept based on guided electromagnetic waves (GEW), in which the waveguide forms a union with the structure to be inspected. Exploiting ultra-wideband signals a surface defect in the area under the waveguide can be detected and accurately localized. This paper presents numerical and experimental GEW results for a straight waveguide focusing on the detection of through holes and cracks with different orientation. It was found that the numerical model qualitatively replicates the experimental S-parameter measurements for holes of different diameters. A parametric numerical study indicates that the crack parameters such as its orientation and width has a significant influence on the interaction of the incident wave with the structural defect. On top, a numerical study is performed for complex-shaped rectangular waveguides including several waveguide bends. Besides a successful damage detection, the damage position can also be precisely determined with a maximum localization error of less than 3%.

Interface debonding defect detection for CFST columns based on EMI measurements: Experiment, numerical simulation and blind inspection in practice

“…Even typical traditional nondestructive test (NDT) methods for various engineering structures including ultrasonic technology (Li et al, 2022), infrared thermography (Li et al, 2020), impact echo testing (Hsieh et al, 2016) and electromagnetic wave testing have shown their abilities in detecting common typical defects such as cracks in concrete and connection failure in steel structures, they are usually ineffective in interface debonding defects detection for CFST members (Castaner and Monni, 2020; Qiu, 2020). Interface debonding defects between fiber polymer and concrete in fiber polymer strengthened reinforced concrete (RC) columns can be sufficiently detected with electromagnetic (EM) wave method.…”

Damage Sensitive Signals for the Assessment of the Conditions of Wind Turbine Rotor Blades Using Electromagnetic Waves

“…In [15], a sensing concept based on guided electromagnetic waves (GEW) is presented to detect material defects such as delaminations, cracks, or inclusions.…”