Ultrasonic Guided Waves in Structural Health Monitoring

Abstract

Ultrasonic Guided Wave inspection and structural health monitoring is being considered today in such natural wave guide structures as plates, multi-layer structures, rods, rails, piping and tubing, an interface, and curved or flat layers on a half space. An increased understanding of the basic physics and wave mechanics associated with guided wave inspection has led to an increase in practical nondestructive evaluation and inspection problems. Computing power today is also making dreams come true, where only a vision was possible decades ago. A principal advantage of guided waves is inspection over long distances with excellent sensitivity from a single probe position. There is also an ability to inspect hidden structures and structures under water, coatings, insulations, and concrete. Basic theoretical aspects of dispersion curve analysis, wave structure, source influence, sensor types and instrumentation possibilities and commercialization ventures will be discussed along with a variety of practical applications on ship hull, containment structures, aircraft, ice detection, pipelines, rail, overlap joints, and crystal manufacture. Phased array focusing in pipes and across elbows will be highlighted. Computational aspects of FEM and BEM analysis for defect classification and sizing analysis will be outlined. Future directions of leave in place sensors and wireless activity will also be presented.

Propagation and scattering of guided waves in composite plates with defects

“…From a single location, the guided waves can cover large areas, which helps to reduce the inspection time. The reflection of the propagating wave at defects enables rapid detection of defects in large structures [14]. This method has been used successfully for the detection of defects in large metal plates and long pipes, i.e., for corrosion and crack detection [15].…”

Ultrasonic Guided Wave Propagation through Welded Lap Joints

“…For this reason, testing for a high level of safety and the reliability of periodical maintenance of the tank and its floor should be performed, in order to avoid corrosion related accidents when hazardous chemical materials might get into the environment and groundwater. In order to avoid this, various NDT methods for the inspection of the construction elements in the petrochemical industry, such as penetrant testing, magnetics [1], eddy current [2], thermography [3,4], radiographic testing [5], acoustic emission [6], and ultrasonic techniques are used [7,8]. The main problems related to the inspection of the storage tanks and their floors using conventional NDT methods is that, in most cases, the tank has to be emptied, cleaned, and made safe for human entry before any inspection could be performed.…”

3D finite element modelling of guided wave scattering at delaminations in composites

“…There exists a need for less time-consuming and more cost-effective non-destructive evaluation (NDE) methods for the monitoring of large composite structures. Guided ultrasonic waves have the potential for the efficient monitoring of large structures [4], as they can propagate over long distances with limited energy loss [5] and are sensitive to changes in the material properties, e.g., bond layer stiffness of a bonded stiffener [6]. High frequency guided waves have been successfully used in single and multi-layered metallic structures [7,8] to detect damage such as fatigue cracks [9][10][11].…”