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Author

Meng Wang

Bio: Meng Wang is an academic researcher from Central South University. The author has contributed to research in topics: Signal & Longitudinal wave. The author has an hindex of 1, co-authored 3 publications receiving 1 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the optimal combination of gyratory parameters that yields the best compaction performance was determined from the orthogonal testing results with the relative importance of major influencing parameters ranked accordingly.
Abstract: The quality of compaction of unbound aggregate materials with permeable gradation plays a vital role in their field performance; however, there are currently few unanimously accepted techniques or quality control criteria available for ensuring adequate compaction of such materials in either laboratory or field applications. This paper presented testing results of a laboratory gyratory compaction study where the combinations of gyratory parameters were properly designed using the orthogonal array theory. Innovative real-time particle motion sensors were employed to record particle movement characteristics during the compaction process and provide a meso-scale explanation about compaction mechanisms. Particle abrasion and breakage were also quantified from particle shape digitized from the three-dimensional (3D) laser scanner before and after compaction. The optimal combination of gyratory parameters that yields the best compaction performance was determined from the orthogonal testing results with the relative importance of major influencing parameters ranked accordingly. Meso-scale particle movement at the upper center and center side positions of the specimen are promising indicators of compaction quality. The gyratory compaction process can be consistently divided into three distinct stages according to both macro-scale performance indicators and meso-scale particle movement characteristics. A statistically significant bi-linear relationship was found to exist between relative breakage index and maximum abrasion depth, whereas the quality of compaction and the extent of particle breakage appear to be positively correlated, thus necessitating the cost-effective balance between them. The results of this study could provide technical insights and guidance to field compaction of unbound permeable aggregates.

7 citations

Journal ArticleDOI
TL;DR: In this paper, the attenuation coefficient of Rayleigh waves is introduced to characterize grain size in heat treated 316L stainless steel, and the measured results are efficient, more stable and less influenced by the surface state when an air-coupled receiver is used.
Abstract: Grain size is an important parameter in evaluating the properties of microstructures in metals. In this paper, the attenuation coefficient of Rayleigh waves is introduced to characterize grain size in heat treated 316L stainless steel. Rayleigh wave attenuation is measured using an angle beam wedge transducer as the transmitter and an air-coupled transducer as the receiver. The results show that the grain size in 316L stainless steel increases due to heat treatment time, the hardness decreases accordingly, and the attenuation coefficient of Rayleigh waves increases. This indicates that the Rayleigh wave attenuation is sufficient in distinguishing the changes in the properties of the heat-treated stainless steel. It is found that compared with the measurement method using an angle beam wedge receiver, the measured results are efficient, more stable and less influenced by the surface state when an air-coupled receiver is used. In addition, comparison results also show that the Rayleigh wave attenuation is more sensitive to changes in material properties than the longitudinal wave attenuation, as the wavelength of the Rayleigh wave is shorter than that of the longitudinal wave at the same frequency.

2 citations

Patent
15 Dec 2020
TL;DR: In this paper, a non-linear pulse reflection measurement device and a calibration device and method for a probe in the device are described, and the results of a water absolute nonlinear-coefficient measurement experiment show that accurate measurement can be realized after the influence of the impedance of the electronic equipment on a transfer function when the probe is used as a receiver is corrected, which plays a role in promoting and referencing the development of a piezoelectric receiving probe inspection technology and the design and construction of a pulse reflection nonlinear measurement system.
Abstract: The invention discloses a non-linear pulse reflection measurement device and a calibration device and method for a probe in the device. The method comprises the steps of firstly obtaining a standard transfer function through a conventional self-reciprocity-based probe calibration mode, selecting another probe for transmitting a signal based on the standard transfer function, and measuring the output current of the calibrated probe under different circuit connections so as to correct the influence of the circuit impedance on the probe transfer function. The result of a water absolute nonlinearcoefficient measurement experiment shows that accurate measurement can be realized after the influence of the impedance of the electronic equipment on a transfer function when the probe is used as a receiver is corrected, and the method plays a role in promoting and referencing the development of a piezoelectric receiving probe inspection technology and the design and construction of a pulse reflection nonlinear measurement system.

Cited by
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Journal ArticleDOI
TL;DR: In this article , SmartRocks were embedded at the bottom of the granular base layer to collect particle motion data during compaction and evaluate the particle response patterns as insights into understanding the compaction mechanism of the unbound aggregate base layer.
Abstract: The quality of base course compaction significantly influences pavement’s overall performance. Compared with conventional compaction methods, the intelligent compaction (IC) uses external accelerometers to track pavement responses during compaction and correlates them with pavement layer characteristics to improve the compaction quality. Very few studies have attempted to present interactions of granular materials from the particle level, i.e., how individual particles are responding under the compactive effort. The recent development of a prototype wireless sensor, SmartRock, made tracking the particle movement at meso-scale possible. Accordingly, this paper has the objective of applying the SmartRock sensors to monitor the motion characteristics (i.e., translation and rotation) of granular particles during the compaction process and evaluate the particle response patterns as insights into understanding the compaction mechanism of the unbound aggregate base layer. The experimental site selected was an airport runway test section, designated as the Smart Runway project located in Hill Air Force Base (AFB) in Layton, Utah, United States. SmartRocks were embedded at the bottom of the granular base layer to collect particle motion data during compaction. Analysis results indicated that particle’s motion behavior was closely related to the compactive effort and material properties. Compaction is a process of gaining interlocking among particles and elasticity in materials, and is achieved through the particle’s three-axial angular position arrangement and vertical translation. The particle movement characteristics observed in the granular base were compared to those in asphalt mixtures, which confirmed the unique responses of bound and unbound pavement layer materials. It is suggested that the characteristics of particle rotation behavior during compaction can potentially be used as a control parameter to monitor compaction conditions.

9 citations

Journal ArticleDOI
15 Aug 2021-Sensors
TL;DR: In this paper, the effect of surface roughness on attenuation and dispersion of Rayleigh wave propagation has been investigated, and it was shown that the relative nonlinearity parameter increased significantly with surface roughs (average asperity heights 0.027-3.992 μm and Rayleigh wavelengths 0.29-1.9 mm).
Abstract: Rayleigh waves are very useful for ultrasonic nondestructive evaluation of structural and mechanical components. Nonlinear Rayleigh waves have unique sensitivity to the early stages of material degradation because material nonlinearity causes distortion of the waveforms. The self-interaction of a sinusoidal waveform causes second harmonic generation, while the mutual interaction of waves creates disturbances at the sum and difference frequencies that can potentially be detected with minimal interaction with the nonlinearities in the sensing system. While the effect of surface roughness on attenuation and dispersion is well documented, its effects on the nonlinear aspects of Rayleigh wave propagation have not been investigated. Therefore, Rayleigh waves are sent along aluminum surfaces having small, but different, surface roughness values. The relative nonlinearity parameter increased significantly with surface roughness (average asperity heights 0.027–3.992 μm and Rayleigh wavelengths 0.29–1.9 mm). The relative nonlinearity parameter should be decreased by the presence of attenuation, but here it actually increased with roughness (which increases the attenuation). Thus, an attenuation-based correction was unsuccessful. Since the distortion from material nonlinearity and surface roughness occur over the same surface, it is necessary to make material nonlinearity measurements over surfaces having the same roughness or in the future develop a quantitative understanding of the roughness effect on wave distortion.

5 citations

Journal ArticleDOI
TL;DR: In this paper , the theoretical and experimental studies of the ballast consolidation under the vibration loading of the sleeper were presented by the 1:2.5 scaled physical model of one sleeper and the corresponding ballast layer box.
Abstract: Abstract During track construction or ballast bed maintenance, ballast layer compaction quality plays an essential role in the following track irregularity accumulation, its lifecycle, and maintenance costs. The ballast compaction process is characterized by its compaction and the accumulation of the stressed state. The elastic wave propagation methods are an effective way for the identification of the ballast bed compaction properties. The paper presents the theoretical and experimental studies of the ballast consolidation under the vibration loading of the sleeper. The practical laboratory study is given by the 1:2.5 scaled physical model of one sleeper and the corresponding ballast layer box. The measurements of ballast pressure and deformations under the vibration loading in the ballast layer and the photogrammetric recording of the ballast flow are carried out. The measurements demonstrate the accumulation of the residual stresses under the ballast layer. Furthermore, the measurements of elastic wave time of flight (ToF) using the shakers under the sleeper and acceleration sensors under the ballast show the substantial increase of the ToF velocities after the tamping process. Moreover, the distribution of the velocities along the sleeper is spatially inhomogeneous. The numeric simulation using the discrete element method (DEM) of the tamping and the testing processes proves the inhomogeneous wave propagation effect. The modeling shows that the main reason for the wave propagation inhomogeneity is the accumulated residual stress distribution and the minor one – the compaction density. Additionally, a method for identifying wave velocity spatial distribution is developed by wave tracing the inhomogeneous medium. The procedures allow ballast identification in the zones outside the shakers.

3 citations

Journal ArticleDOI
TL;DR: In order to overcome the limitations of crumb rubber modified asphalt (CRMA) in application such as weak storage stability and construction workability, liquid rubber (LR) was adopted to improve the properties of base asphalt binder in this paper .

2 citations

Journal ArticleDOI
TL;DR: In this paper , the authors investigated the dynamic responses of particle in aggregate mixture during compaction by using a Smart Aggregate and found that compaction methods, adjacent particles' size and aggregates packing had significant influence on the particle movement in mixture.

1 citations