Impedance and attenuation profile estimation of multilayered material from reflected ultrasound

Chen

Materials Research Innovations

2015

Owing to the reason that multiple reflection waves are unable to separate, and transfer function and time-delay spectrum are developed, adhesion interface characteristic of the thin layer medium is difficult to detect. Acoustics characteristic of the thin layer is studied with the ultrasonic longitudinal testing method to solve this problem. The results show that the fundamental acoustic parameters of the thin layer, such as sound velocity, reflection coefficient and attenuation coefficient, are obtained based on transfer function and time-delay spectrum. The analytical results show that these parameters mentioned above can characterise adhesion interface quality of the thin layer. The maximum values of the transfer function are unchanged, and its curve is flatter with the increasing of the reflection coefficient. The maximum delayed time increases with the increasing of the reflection coefficient, and the maximum delayed time is more sensitive to the reflection time coefficient variation than the transfer function is.

Section: Introductionmentioning

confidence: 99%

Measurement of the interface characteristic base on ultrasonic longitudinal wave

Chen

Materials Research Innovations

2015

Transactions of the Institute of Measurement and Control

“…As the acoustic wave propagating through the interface of inclusions with different acoustic impedance and geometrical size, several phenomena like attenuation, reflection and scattering may occur, based on which three major modalities are categorized: transmission (Svilainis et al, 2018), reflection (Chen et al, 1991) and scattering (Gunarathnee and Chiristidis, 2001). The effect of acoustic scattering only occurs obviously when the size of scatters is similar to the wave length, which is not a common scenario in the application of multiphase flow.…”

Section: Introductionmentioning

confidence: 99%

Continuous-wave ultrasonic tomography for oil/water two-phase flow imaging using regularized weighted least square framework

Líu

Tan

2019

Two-phase flow is a regime that commonly existed in many applications of process industry, on which the technique of ultrasonic tomography (UT) could provide reliable measurement with benefits of non-invasion, non-radiation and low-cost. In order to provide considerable visualization of low acoustic impedance contrast configurations in two-phase flow, a regular weighted simultaneous algebraic reconstruction technique (RW-SART) using continuous-wave excitation is proposed and presented in detail. With measurement strategy and formulized reconstruction model introduced, the measurement system is introduced with modification on continuous-wave excitation module and fan-beam angle transducers. A regularized weighted least square (RWLS) framework combining total variation (TV) regularization and SART reconstruction is derived and presented in detail to address the problem that under-determined and ill-conditioned situation couldn’t be resolved simultaneously. Both numerical simulation and experimental investigation are conducted to validate the feasibility of continuous-wave excitation and the improvement of proposed reconstruction strategy, from which the distribution of oil-water two-phase flow is effectively reconstructed. The implementation of measurement system provides an option of continuous high-voltage excitation and measurement in UT. By utilizing both the geometric information and penalty constraint, the proposed reconstruction approach provides a framework that introduces regularization information to the algebraic iteration reconstruction. Consequently, it has better reconstruction result than TV, Landweber, L1, filtered back projection (FBP) and SART method.

“…The coating performance parameters were characterized using proilar to the pulse-echo is used to detect properties of the thick material, unfortunately, which is cess of ultrasonic propagation in the medium in most case, for example, the sound velocity, thickness of the coating. However, the results show that [2,3] : the conventional ultrasonic methods simhelpless for the thin layer owing to most of its thin and even a number of heterogeneous thin layer. The mutual superposition of ultrasonic echo derived from the different interface and interference in each other.…”

Section: Introductionmentioning

confidence: 99%

The Chrome Thin Coating Characteristics Using Ultrasonic Testing

2012

AMM

According to the different thickness of the thin coatings, the echo signal of ultrasonic testing was extracted. The sound velocity in the coating medium was obtained by solving the mathematical model for transfer function and the time delay spectrometry method, and the coating thickness was calculated, the comparison error of the calculated thickness and the actual thickness, combined with the actual thickness of the coating. The results showed that, two kinds of testing methods are able to detect thin coating thickness.