Guided Waves for Nondestructive Testing – Experiment and Analysis

Abstract

Use of ultrasonic waves is continuously increasing for nondestructive evaluation (NDE) and structural health monitoring (SHM) in civil, aerospace, electrical, mechanical and bioengineering applications. Between bulk waves and guided waves, the latter is becoming more popular for NDE/SHM applications because the guided waves can propagate long distances and reach dif fi cult to access regions. Recent advances in the research related to nondestructive testing (NDT) of composites and metals are discussed in this paper. To analyze the experimental results one often needs to understand the mechanics of wave propagation in various structures. Unfortunately, only for simple structures, such as homogeneous and layered halfspaces, plates, rods and pipes, the analytical solutions are available. Complex structural geometries with internal defects are dif fi cult to solve analytically or numerically by the popular fi nite element method because at high frequencies the size of the fi nite elements becomes prohibitively small. An alternative mesh-free technique called the distributed point source method (DPSM) is being developed for solving such problems and is discussed here in addition to the experimental results.

Time domain analysis of nonlinear frequency mixing in a slender beam for localizing a breathing crack

“…where k i ʼs are the roots of the characteristic equations of ODEs stated in equation (6). The subscript j, indicating the quantities pertaining to the jth translate of scaling function is hereafter omitted for maintaining brevity.…”

“…The literature concerned with the forward and the inverse analysis of nonlinear bulk wave-crack interactions is matured [2][3][4][5]. The present day health monitoring practices however prefer guided waves over the bulk waves, owing to their ability to scan larger area while maintaining the sensitivity to the defect size [6]. Although the studies addressing the linear interactions of guided waves with crack are well documented in the literature [7], the nonlinear interactions of guided wave with crack are comparatively less explored, either experimentally [8,9] or theoretically [10][11][12][13].…”

Modal frequencies of fiber-reinforced polymer pipes with wall-thinning using a wavelet-based finite element model

“…Moreover, thermography 11 and microwave electromagnetic imaging 12 have been employed to investigate the damage in composite structures. However, the available non-destructive testing (NDT) methods have difficulties associated with their application in the field, as reported for radiography-based techniques, 7,8 ultrasonic tomography 13 and for infrared thermography. 14 In addition, the available NDT methods have limitations with respect to area of coverage, large thickness, and interpretation of their measurements.…”