On the development and testing of a guided ultrasonic wave array for structural integrity monitoring

Abstract

Abstract-The prototype of a guided ultrasonic wave array for the structural integrity monitoring of large, platelike structures has been designed, built, and tested. The development of suitably small transducers for the excitation and measurement of the first antisymmetric Lamb wave mode A0 is described. The array design consists of a ring of 32 transducers, permanently bonded to the structure with a protective membrane, in a compact housing with the necessary multiplexing electronics. Using a phased addition algorithm with dispersion compensation and deconvolution in the wavenumber domain, a good dynamic range can be achieved with a limited number of transducers. Limitations in the transducer design and manufacture restricted the overall dynamic range achieved to 27 dB. Laboratory measurements for a steel plate containing various defects have been performed. The results for standard defects are compared to theoretical predictions and the sensitivity of the array device for defect detection has been established. Simulated corrosion pitting and a defect cut with an angle grinder simulating general corrosion were detected.

In situ 2-D piezoelectric wafer active sensors arrays for guided wave damage detection

“…Experimentally, an array containing 16 transmitter and 32 receivers arranged in concentric rings were used for exciting and detecting S0 Lamb wave mode. A same array configuration but using piezoelectric transducers for generating and detecting A0 Lamb wave mode was used for the structural integrity monitoring later by Fromme et al [21]. Wilcox et al [22] also developed a technique recently for characterizing reflectors with sub-wavelength dimensions achieved by post-processing the complete data set of time traces.…”

Flat lens for pulse focusing of elastic waves in thin plates

“…Here, compressional and shear components of the wave are linked by stress-free boundary conditions on the limiting surfaces to produce dispersive Lamb modes, leading to simplification of the tensor equations into a fourth order differential operator such as those of Timoshenko or Graff. 21,22 Beyond the interest in diffractive tomography 23 and non-destructive testing 24 of large plate-like structures, control of flexural waves 25 in structured plates has become an increasingly fashionable topic in the past few months with the first experimental validation 26 of the theoretical proposal for cloaking in thin plates. 27,28 Recently, negative refraction in elastic plates was reported at an interface via mode conversion 29 or across a prism-shaped phononic crystal.…”

Modeling and identification of uniform corrosion damage on a thin plate using a Bayesian framework

“…Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jsvi waves [1][2][3], refracted light [4,5], magnetic fields [6], and thermal radiation [7]. All these methods, and the Lamb wave techniques in particular, have received significant attention in the literature; as such, the references cited herein serve as recent, relevant examples, rather than an exhaustive survey.…”