Characterization of Nonlinear Ultrasonic Diffuse Energy Imaging

Abstract

Nonlinear ultrasonic diffuse energy imaging is a highly sensitive method for the measurement of elastic nonlinearity. While the underlying principles that govern the technique are understood, the precise behavior and sensitivity have not previously been quantified. This paper presents experimental, theoretical, and numerical modeling studies undertaken to characterize nonlinear diffuse energy imaging. The influence of incoherent noise, elastic nonlinearity, and instrumentation error are quantified. This paper enables the prediction of spatial sensitivity, aperture, and amplitude dependence of the measurement, all of which moves the technique toward industrial viability. Furthermore, while previous studies have focused on the detection of closed cracks, the ultimate aim for nonlinear ultrasonic imaging in application to material testing is the detection of damage precursors, which requires a sensitivity to weak classical nonlinearity. This paper identifies the experimental requirements necessary for this to be achieved, greatly expanding the potential applicability of nonlinear ultrasonic array imaging.

Imaging of three-dimensional crack open/closed distribution by nonlinear ultrasonic phased array based on fundamental wave amplitude difference

“…[41][42][43][44] Therefore, a closed crack can be selectively measured by leveraging the incident-waveamplitude dependence of fundamental responses. 24,25,[35][36][37][38][39][40] To implement this concept experimentally, a way of changing the incident wave amplitude at a transmission focal point must be carefully considered. The easiest way is to select multiple excitation voltages that are applied to each piezoelectric element.…”

“…In order to overcome the aforementioned difficulties, the nonlinear incident-wave-amplitude dependence of the fundamental response has been utilized. 24,25,[33][34][35][36][37][38][39][40] We refer to this technique as fundamental wave amplitude difference (FAD). FAD can indirectly infer all the nonlinear components (i.e.…”

“…multiple higher harmonics and subharmonics) originating from the nonlinearity of a closed crack by measuring the deviation from the linearity of the relationship between the fundamental response obtained by PA imaging and the incident wave amplitude since the generation of the nonlinear components can be regarded as the energy transfer between the fundamental and nonlinear components. 24,25,[35][36][37][38][39][40] Furthermore, FAD can infer the dissipation of the mechanical (acoustical) energy into the thermal one. [41][42][43][44] The dissipation corresponds to the heat generation due to the ultrasonically induced friction between crack faces.…”

An analytical approach to reconstruction of axisymmetric defects in pipelines using T(0, 1) guided waves

“…Ultrasonic inspection, as an effective and nondestructive evaluation method, has been applied to structural health monitoring and damage detection. According to the properties of elastic waves, ultrasonic inspection mainly includes bulk waves inspection [9][10][11][12] , guided waves inspection [13][14][15][16][17] , and nonlinear ultrasonic inspection [18][19][20][21] . Due to the non-dispersion characteristics, guided waves inspection [22] has a unique advantage over other methods for testing large structures and it is a promising method for detecting long-distance transportation pipelines.…”

Multi-mode nonlinear ultrasonic phased array for imaging closed cracks

“…Recently, the closed crack imaging methods of combining nonlinear ultrasonics with phased array technique have been proposed, [14][15][16][17][18][19][20][21][22][23][24][25][26] where the first implementation is subharmonic phased array for crack evaluation (SPACE). [14][15][16][17][18][19][20] Thus far, most of nonlinear ultrasonic phased array imaging has been carried out on the basis of the measurement of the longitudinal waves that are nonlinearly scattered at closed cracks by longitudinal wave incidence.…”