Multimode dispersion compensated pulse-echo guided wave inspection

2015 ◽  
Author(s):  
R. A. Roberts ◽  
E. Peters ◽  
D. E. Chimenti
Keyword(s):  
Guided Wave ◽  
Pulse Echo

scholarly journals 10 MHz Thin-Film PZT-Based Flexible PMUT Array: Finite Element Design and Characterization

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4335
Author(s):  
Jeong Nyeon Kim ◽  
Tianning Liu ◽  
Thomas N. Jackson ◽  
Kyusun Choi ◽  
Susan Trolier-McKinstry ◽  
...  
Keyword(s):  
Finite Element ◽  
Lead Zirconate Titanate ◽  
Focal Length ◽  
Spectral Response ◽  
Guided Wave ◽  
Center Frequency ◽  
Depth Of Field ◽  
High Frequency Ultrasound ◽  
Pulse Echo ◽  
2D Array

Piezoelectric micromachined ultrasound transducers (PMUT) incorporating lead zirconate titanate PbZr0.52Ti0.48O3 (PZT) thin films were investigated for miniaturized high-frequency ultrasound systems. A recently developed process to remove a PMUT from an underlying silicon (Si) substrate has enabled curved arrays to be readily formed. This research aimed to improve the design of flexible PMUT arrays using PZFlex, a finite element method software package. A 10 MHz PMUT 2D array working in 3-1 mode was designed. A circular unit-cell was structured from the top, with concentric layers of platinum (Pt)/PZT/Pt/titanium (Ti) on a polyimide (PI) substrate. Pulse-echo and spectral response analyses predicted a center frequency of 10 MHz and bandwidth of 87% under water load and air backing. A 2D array, consisting of the 256 (16 × 16) unit-cells, was created and characterized in terms of pulse-echo and spectral responses, surface displacement profiles, crosstalk, and beam profiles. The 2D array showed: decreased bandwidth due to protracted oscillation decay and guided wave effects; mechanical focal length at 2.9 mm; 3.7 mm depth of field for -6 dB; and -55.6 dB crosstalk. Finite element-based virtual prototyping identified figures of merit—center frequency, bandwidth, depth of field, and crosstalk—that could be optimized to design robust, flexible PMUT arrays.

PULSE-ECHO REFLECTIONOFTHE SH0 GUIDED WAVE MODE FROM A PART-THICKNESS ELLIPTICAL DEFECT IN A PLATE

2010 ◽  
Author(s):  
J. Ma ◽  
P. Cawley ◽  
M. Lowe ◽  
Donald O. Thompson ◽  
Dale E. Chimenti
Keyword(s):  
Wave Mode ◽  
Guided Wave ◽  
Pulse Echo ◽  
Part Thickness

Guided wave-based detection of delamination and matrix cracking in composite laminates

2010 ◽  
Vol 225 (1) ◽  
pp. 123-131 ◽  
Author(s):  
T Wandowski ◽  
P Malinowski ◽  
P Kudela ◽  
W Ostachowicz
Keyword(s):  
Composite Laminates ◽  
Guided Waves ◽  
Guided Wave ◽  
Matrix Cracking ◽  
Detection Methods ◽  
Localization Algorithm ◽  
Reflected Waves ◽  
Signal Processing Algorithms ◽  
Pulse Echo ◽  
Pulse Echo Method

The aim of this article was a numerical and experimental study of the active damage detection methods based on piezoelectric elements attached to a composite laminate. In considered case, guided waves were excited and received in a structure using pulse-echo method. It means that after exciting a structure with a pulse, an array of sensors located on a structure was used to ‘listen' for reflected waves coming from discontinuities. The main part of structural health monitoring system is signal-processing algorithms, which allow to detect and localize damage. Algorithm applied in this research results in special maps that indicate damage location. In this article, a damage localization algorithm was described and experimentally tested. The proposed method was successfully tested on a carbon—epoxy part of a helicopter.

Ultrasonic Circumferential Guided Wave for Pitting-Type Corrosion Imaging at Inaccessible Pipe-Support Locations

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
K. Shivaraj ◽  
Krishnan Balasubramaniam ◽  
C. V. Krishnamurthy ◽  
R. Wadhwan
Keyword(s):  
Guided Waves ◽  
Pipe Wall ◽  
Element Model ◽  
Higher Order ◽  
Guided Wave ◽  
Structural Layout ◽  
Ultrasonic Guided Wave ◽  
Experimental Parameters ◽  
Data Acquisition Card ◽  
Pulse Echo

A higher order cylindrically guided ultrasonic wave was used for the detection and sizing of hidden pitting-type corrosion in the hidden crevice regions (between the pipe and the pipe supports) without lifting or disturbing the structural layout arrangement of the pipelines. The higher order circumferential guided waves were generated using a piezoelectric crystal based transducer, located at the accessible top region of the pipes, in a pulse-echo mode. By studying the experimental parameters such as dispersion, particle displacement, and wavelength of the ultrasonic guided wave modes, an appropriate higher order mode was selected for excitation using an appropriately designed acrylic angle wedge that conforms to the pipe’s outer curvature. A manual pipe crawler was designed with a provision for holding the wedge, and the essential hardware such as data acquisition card, encoder, etc., was integrated with the system so that the corrosion was mapped in real time during the scanning of the pipes. The system was validated on pipes ranging from 6in.to24in. outer diameters of wall thicknesses up to 12mm, by mapping defects as small as 1.5mm diameter and 25% penetration wall thickness. A 2D finite element model using ABAQUS® was used to understand the wave propagation in pipe wall and its interaction with pinhole-type defects.

EMAT Generation of Horizontally Polarized Guided Shear Waves for Ultrasonic Pipe Inspection

1998 ◽  
Author(s):  
Julie Gauthier ◽  
Vasile Mustafa ◽  
Ahmad Chabbaz ◽  
D. Robert Hay
Keyword(s):  
Mode Selection ◽  
Single Mode ◽  
Guided Wave ◽  
Sh Wave ◽  
Sh Waves ◽  
Acoustic Transducers ◽  
Ultrasonic Guided Wave ◽  
Cylindrical Steel ◽  
Pulse Echo ◽  
Multi Mode

In this work, an ultrasonic guided wave inspection technique was evaluated to detect and locate defects in pipes using SH (Horizontally polarized Shear) plate waves. Electromagnetic Acoustic Transducers (EMATs) were designed and constructed for bi-mode SH waves applications. These probes were used to generate a single mode at a time. Advantages of SH waves, guided by the wall surfaces for circumferential propagation and full volume inspection, are demonstrated in the pulse-echo setup. Mode selection criteria were investigated to tune the SH waves to the geometry of the inspection specimen Examples of mode selection based on the interaction characteristics of SH wave modes with a defect are described. An application of multi-mode inspection for geometrical parameter evaluation (length, depth and orientation) of individual cracks was also demonstrated. The experimental work was performed on cylindrical steel pipe samples having several types of defects ranging from through wall cracks to shallow cracks (10% of wall thickness) both in the circumferential and longitudinal directions. Results from laboratory investigation of the influence of defect depth and orientation on reflectivity of various modes of SH waves are reported. Multi-mode SH-wave inspection is shown to be capable of detecting shallow discontinuities (microcracks) and of locating defects accurately. Inspection results on a pipe section are represented as 3-D images with B-Scan projections and their interpretation is discussed.

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