Electromagnetics

The University of Cincinnati Centre for NDE has an exceptionally well-equipped electromagnetic NDE lab. The lab specializes in developing novel damage detection and material characterization techniques for both inspection and monitoring. The Center has expertise in eddy current, potential drop (ACPD and DCPD), microwave, ACFM, magnetic flux leakage, thermoelectric and Hall coefficient measurements. We work within the fields of aerospace, oil & gas, power generation. Amongst others, we have worked with the Federal Aviation Administration, The Airforce Research Laboratory, Department of Energy, Department of Defense, General Electric, Rolls-Royce, Honeywell, Electric Power Research Institute.

AdobeStock_124069885.jpeg
Non-Destructive Residual Stress Profiling

The Center has world leading expertise in non-destructive residual stress measurement. The center is currently leading an effort to use a multi-modal electromagnetic technique that incorporates eddy-current and Hall coefficient measurements. The approach builds on decades of research experience and has shown very promising results. New analytical methods and experimental methods have been established.

Inversion procedure for dual-mode electromagnetic nondestructive characterization of shot-peened IN718

D Velicheti, PB Nagy, and W Hassan, NDT&E Int. 101, 17-28, 2019.

High-frequency Hall coefficient measurement using inductive sensing for nondestructive materials characterization

D Velicheti, PB Nagy, and W Hassan, NDT&E Int. 94, 109-119, 2018

Long Range Microwave Inspection of Corrosion Under Insulation

Corrosion under insulation (CUI) is a widespread problem in the oil and gas industry. Often pipes are fitted with a layer of insulation material protected by an external metallic cladding to maintain the fluid that they carry at constant temperature. Water infiltration through the cladding can cause corrosion of the inner pipe, therefore it is necessary to inspect pipeline for CUI. The inspection can be prohibitively expensive due to the need for removing the cladding and insulation to access the pipe with conventional NDE methods. We have developed a new approach that is based on the rationale that water is a necessary precursor to CUI and therefore it is desirable to detect it in order to prevent CUI formation in the first instance. Thanks to the conductivity of the pipe and cladding, the insulated pipeline naturally forms a large coaxial waveguide which supports the propagation of microwave signals along the insulation layer; the latter being typically transparent to microwave radiation. The microwave signal, which is excited by an array of antennas inserted in the insulation, travels along the pipeline and is reflected back towards the array upon impinging on an area of wet insulation. By timing the journey of the reflected signal, the location of the water volume can be determined according to the conventional radar principle.

An Experimental Model for Guided Microwave Backscattering from Wet Insulation in Pipelines

SM Bejjavarapu and F Simonetti, Journal of Nondestructive Evaluation, 33, 583–596, 2014

Microwave.png
Electromagnetic Characterization of Material Aging in Power Stations 

The mechanical properties of power station materials will degrade with long term thermal and/or irradiation exposure. The Center has been developing a suite of electromagnetic methods that have proven sensitivity to material aging phenomena. The techniques, including thermoelectric, electrical conductivity and magnetic permeability are all suitable for permanent installation and can be combined into a simple and robust permanently installable sensor for real-time degradation monitoring.

J Corcoran and PB Nagy, Passive thermoelectric power monitoring for material characterisation, Structural Health Monitoring. 18, 1915–1927 (2019)

J Corcoran, S Raja, and PB Nagy, Improved thermoelectric power measurements using a four-point technique,  NDT&E Int. 94, 92-100 (2018).

PD Station 2.jpg