Simultaneous measurement of ultrasonic longitudinal wave velocities and thicknesses of a two layered media in the absence of an interface echo
14 Oct 2010-Review of Scientific Instruments (American Institute of Physics)-Vol. 81, Iss: 10, pp 105101-105101
TL;DR: The proposed method works in the absence of an interface echo and requires the total thickness of the sample to be known, and is found to be sensitive to the total sample thickness but fairly insensitive to noise in the data.
Abstract: A measurement technique has been developed to extract the phase information of successive echoes for the simultaneous estimation of thicknesses and ultrasonic velocities of individual layers in a two layered media. The proposed method works in the absence of an interface echo and requires the total thickness of the sample to be known. Experiments have been carried out on two layered samples of white cast iron and gray cast iron with layer thickness variation in the range of 2-8 mm for total thickness variation in the range of 12-13 mm. Comparison with micrographs of a few samples confirmed the model predictions. The model is found to be sensitive to the total sample thickness but fairly insensitive to noise in the data.
Citations
More filters
TL;DR: The nondestructive method using ultrasonic testing to simultaneously measure thickness, density, sound velocity and attenuation through V(z,t) data, recorded by time-resolved acoustic microscopy is proposed.
19 citations
TL;DR: A PSO‐based least squares estimation using the ultrasonic reflection spectrum to make simultaneous measurement of multi‐layered material and the results have been compared to analyze the errors of the estimated parameters.
7 citations
TL;DR: In this paper, a set of ultrasonic reflection signal acquisition and processing circuit and wavelet packet analysis and reconstruction software is designed to suppress noise and improve signal to noise ratio, which can obtain a more pure reflection of the ultrasonic bottom signal, thereby enhance the accuracy of thickness measurement.
Abstract: The corrosion pits, rust, slag and dust of metal surface can cause a sharp bottom echo noise signal, and affect the accuracy of the thickness measurement values. This paper designed a set of ultrasonic reflection signal acquisition and processing circuit and wavelet packet analysis and reconstruction software, which can suppress noise and improve signal to noise ratio. Experiments show that the signal processing circuit and the wavelet packet technologies in non-smooth surface metal plate ultrasonic thickness measurement is effective and useful, which can obtain a more pure reflection of the ultrasonic bottom signal, thereby enhance the accuracy of thickness measurement.
4 citations
TL;DR: In this article, the authors applied the all-optical (AO) laser ultrasonic (LU) technique for the characterization of the sub-mm layers in a multilayer structure.
3 citations
21 Dec 2016
TL;DR: In this paper, the authors derived analytically a transcendental equation, which positive roots are the spectrum of torsional and longitudinal natural frequencies of cantilever composed of an arbitrary number of layers with the piecewise constant mechanical properties, densities and thicknesses.
Abstract: Here, we derived analytically a transcendental equation, which positive roots are the spectrum of torsional and longitudinal natural frequencies of cantilever composed of an arbitrary number of layers with the piecewise constant mechanical properties, densities and thicknesses. This transcendental equation has been obtained in the Laplace image space and the one connects the mechanical properties, density and layer thickness. The present solution can be particularly useful for either a non-destructive material testing or design of the cantilever structures.
Cites methods from "Simultaneous measurement of ultraso..."
...Among NDTs, ultrasonic methods are commonly employed to characterize multilayered structures [3-17]....
[...]
References
More filters
Book•
28 Jun 1990
TL;DR: Inverse scattering problems in planar and spherically layered media have been studied in this article, where Dyadic Green's functions have been applied to the mode matching method to solve the problem.
Abstract: Preface. Acknowledgements. 1: Preliminary background. 2: Planarly layered media. 3: Cylindrically and spherically layered media. 4: Transients. 5: Variational methods. 6: Mode matching method. 7: Dyadic Green's functions. 8: Integral equations. 9: Inverse scattering problems. Appendixes A, B, C, & D. Index
3,872 citations
Book•
01 Jan 1969
TL;DR: In this article, the authors describe the physical fundamentals of ultrasonics and materials up to the most sophisticated methods for nondestructive testing of solid material using ultrasonic waves for defects such as cavities, nonbonding, and strength variations.
Abstract: Nondestructive testing of solid material using ultrasonic waves, for defects such as cavities, nonbonding, and strength variations, is treated in this book from the physical fundamentals of ultrasonics and materials up to the most sophisticated methods. The book is written at a level which should make it accessible to readers with some knowledge of technical mathematics. Physical laws are explained in elementary terms, and more sophisticated treatments are also indicated. After the fundamentals, instrumentation and its application is extensively reported. Tricks and observations from thirty years of experience in the field are included. The third part of the book presents test problems related to special materials or ranges of modern heavy industry, including recent applications such as those in nuclear power plants. This fourth edition features improved presentation of certain fundamental physical facts, updated reports on electronic instrumentation, and new applications in the nuclear and space industries.
1,751 citations
Patent•
01 Aug 1986TL;DR: An ultrasonic apparatus for testing a material comprises an oscillator (10) which generates a selected frequency in the ultrasonic range, and a transducer (1) is connected to the oscillator for applying an ultrasonic signal to the material and for receiving an echo signal back from the material.
Abstract: An ultrasonic apparatus for testing a material comprises an oscillator (10) which generates a selected frequency in the ultrasonic range. A transducer (1) is connected to the oscillator (10) for applying an ultrasonic signal to the material and for receiving an echo signal back from the material. A phase detector (5) receives the echo signal and an in-phase oscillator signal to generate a first display signal, and a phase detector (6) receives a quadrature signal (90° out of phase from the oscillator signal) and the echo signal to generate a second display signal. The first and second display signals are utilised in a visual display, such as a cathode ray tube (8), to generate an image. The image changes according to the phase shift between the ultrasonic signal transmitted into the material and the echo signal, which, in turn, can be utilised to determine the presence and depth of a flaw or boundary in the material.
1,017 citations
TL;DR: In this article, a single-transmitter-multiple-receiver (STMR) compact structural health monitoring (SHM) array is used to reconstruct the elastic moduli of orthotropic plate structures.
Abstract: The reconstruction of all nine unknown elastic moduli of orthotropic plate structures has been achieved using a single-transmitter-multiple-receiver (STMR) compact structural health monitoring (SHM) array. This method uses the velocity measurement of the fundamental guided Lamb wave modes (S0 and A0), generated from a central transmitter, and received by a sparse array of receivers that encircle the transmitter. The measured velocities are then used in an inversion algorithm based on genetic algorithms. A prototype compact STMR array was developed and used in the measurement. Simulated data were used to demonstrate the feasibility of the technique. Experiments were conducted on 3.15 mm graphite–epoxy composite plate using a PZT based STMR array as well as laser vibrometer based displacement measurement. Experimental Lamb wave velocity data were used to validate the present technique. This technique finds application in the areas of material characterization and SHM of anisotropic plate-like structures used in aerospace and automobile components made using fiber reinforced composites.
55 citations