Development of an Automated Eddy Current Structural Health Monitoring Technique with an Extended Sensing Region for Corrosion Detection

Abstract

The process of performing nondestructive evaluation (NDE) on a structural system is a well developed and continuously growing field. One very prominent method of performing NDE on a structure is through the use of eddy currents. Eddy current NDE methods are commonly applied to aircraft during maintenance checks in order to identify the formation of cracks, corrosion, or degradation of rivets. Structural health monitoring (SHM) takes NDE a step further and is a process of periodically or continuously monitoring and assessing the performance and safety of a structural system based on data obtained from a sensing system integrated into the structure. Here a method of integrating an eddy current sensing system into the structure such that the structure can be remotely monitored in an automated way is developed. The development of this sensor technology is novel because it can be automated and has a sensing region far larger than the sensor footprint. While earlier studies have integrated eddy current NDE sensors into various structures, all of these studies have developed sensors that can only detect damage directly under the sensor location, which makes SHM of the structure unrealistic. The eddy current senor is demonstrated to identify both corrosion and damage in the form of a small hole well outside the sensors footprint. Furthermore, the statistical variation in the measurements is shown to be very small making the ability to distinguish real damage from false predictions.

Corrosion Monitoring of Steel Structure Coating Degradation

“…Modern railway systems tend to employ various monitoring techniques generally termed as structural health monitoring [5]. Various principles of detection are being used such as acoustics [6], IR thermography [7,8], eddy currents [9] and various other, mainly MEMStechnology based sensors where the wireless integration provides a complete framework [10][11][12][13]. Corrosion hazard represents only one, often underestimated, topic of structural health monitoring [14] and is often implemented in reinforced concrete structures [15][16][17].…”

Shape memory alloy sensory particles for damage detection: Experiments, analysis, and design studies

“…In the aerospace industry, the two most popular techniques involve the use of ultrasonic 8–11 and eddy current testing. 8,12–14 While effective, these methods require the attachment of sensors to a component, which adds weight and system complexity while also altering the structural integrity or overall performance. Additionally, both methods can fail to detect structural defects that lie parallel to the source of the ultrasonic waves/magnetic fields.…”

Experimental study on identifying cracks of increasing size using ultrasonic excitation

“…Many damage identification techniques have been developed using various types of inspection methods such as guided Lamb wave, 3 – 5 natural frequency, 6 – 8 eddy current, 9,10 and fiber optics. 11 Methods based on ultrasonic guided wave propagation have shown promises in identifying general parameters involved in many types of flaws.…”