Numerical investigation of the effect of heterogeneity on the attenuation of shear waves in concrete

Asadollahi, Aziz; Khazanovich, Lev

doi:10.1016/j.ultras.2018.07.011

Cited by 26 publications

(10 citation statements)

References 28 publications

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“…According to the frequency application range when using ultrasonic to detect concrete [ 21 ], this system adopts 50K-P28F 50 kHz ultrasonic probes. The ultrasonic transmission method has been used for detection.…”

Section: Description Of the Ultrasonic Detection Systemmentioning

confidence: 99%

Design and Performance Analysis of an Ultrasonic System for Health Monitoring of Concrete Structure

Zhao

Zheng

et al. 2021

Sensors

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The development and research of an ultrasonic-based concrete structural health monitoring system encounters a variety of problems, such as demands of decreasing complexity, high accuracy, and extendable system output. Aiming at these requirements, a low-cost extendable system based on FPGA with adjustable system output has been designed, and the performance has been evaluated by different assessment parameters set in this paper. Besides the description of the designed system and the experiments in air medium, the residual similarity and Pearson correlation coefficients of experimental and theoretical data have been used to evaluate the submodules’ output. The output performance of the overall system is evaluated by the Pearson correlation coefficient, root-mean-square error (RMSE), and magnitude-squared coherence with 40 experimental data. The maximum, median, minimum, and mean values in three-parameter datasets are analyzed for discussing the working condition of the system. The experimental results show that the system works stably and reliably with tunable frequency and amplitude output.

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Section: Description Of the Ultrasonic Detection Systemmentioning

confidence: 99%

Design and Performance Analysis of an Ultrasonic System for Health Monitoring of Concrete Structure

Zhao

Zheng

et al. 2021

Sensors

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“…velocity with respect to a homogeneous material [14][15][16][17][18]. Ultrasonic tests in direct transmission mode were conducted on all specimens to verify the degree of homogeneity and the presence of cracks or holes.…”

Section: Specimen Quality Assessmentmentioning

confidence: 99%

“…The size of the coarse aggregate of concrete has been shown to be significant in wave propagation and attenuation [17]. Differences between mortar and concrete are observed in experiments at high frequencies (> 100 kHz), and a marked attenuation of the shear waves due to scattering in the high frequency range > 20 kHz was revealed by numerical investigations involving standard concrete [18]. In the present investigation the focus is on the low sonic frequency range, where the differences between concrete and mortar are not relevant.…”

Section: Introductionmentioning

confidence: 99%

Experimental Validation of the Attenuation Properties in the Sonic Range of Metaconcrete Containing Two Types of Resonant Inclusions

et al. 2020

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Background Metaconcrete is a new concept of concrete, showing marked attenuation properties under impact and blast loading, where traditional aggregates are partially replaced by resonant bi-material inclusions. In a departure from conventional mechanical metamaterials, the inclusions are dispersed randomly as cast in the material. The behavior of metaconcrete at supersonic frequencies has been investigated theoretically and numerically and confirmed experimentally. Objective The feasibility of metaconcrete to achieve wave attenuation at low frequencies demands further experimental validation. The present study is directed at characterizing dynamically, in the range of the low sonic frequencies, the—possibly synergistic—effect of combinations of different types of inclusions on the attenuation properties of metaconcrete. Methods Dynamic tests are conducted on cylindrical metaconcrete specimens cast with two types of spherical inclusions, made of a steel core and a polymeric coating. The two inclusions differ in terms of size and coating material: type 1 inclusions are 22 mm diameter with 1.35 mm PDMS coating; type 2 inclusions are 24 mm diameter with 2 mm layer natural rubber coating. Linear frequency sweeps in the low sonic range (< 10 kHz), tuned to numerically estimated inclusion eigenfrequencies, are applied to the specimens through a mechanical actuator. The transmitted waves are recorded by transducers and Fast-Fourier transformed (FFT) to bring the attenuation spectrum of the material into full display. Results Amplitude reductions of transmitted signals are markedly visible for any metaconcrete specimens in the range of the inclusion resonant frequencies, namely, 3,400-3,500 Hz for the PDMS coating inclusions and near 3,200 Hz for the natural rubber coating inclusions. Specimens with mixed inclusions provide a rather uniform attenuation in a limited range of frequencies, independently of the inclusion density, while specimens with a single inclusion type are effective over larger frequency ranges. With respect to conventional concrete, metaconcrete reduces up to 90% the amplitude of the transmitted signal within the attenuation bands. Conclusions Relative to conventional concrete, metaconcrete strongly attenuates waves over frequency bands determined by the resonant frequencies of the inclusions. The present dynamical tests conducted in the sonic range of frequencies quantify the attenuation properties of the metaconcrete cast with two types inclusions, providing location, range and intensity of the attenuation bands, which are dependent on the physical-geometric features of the inclusions.

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“…Concrete, the most widely used building material [3,4], has a heterogeneous structure that consists of its cement matrix as well as aggregates and pores [5]. These heterogeneities cause scattering of acoustic waves that are coupled into the specimen, which increases with decreasing wavelength of the ultrasonic signal [6]. In order to retain a sufficient signal-to-noise ratio (SNR) for time-of-flight (TOF) measurements, the frequency of the signal applied in NDT-CE applications is limited to the lower ultrasonic range, commonly between 20 kHz and 150 kHz [7].…”

Section: Introductionmentioning

confidence: 99%

“…When these tests are conducted at an existing structure, the travel path of the wave can be in the range of tens of centimeters up to several meters [8]. In addition to limiting the applicable wave types to bulk waves in many cases [2], the large dimensions of the specimens require the insertion of large acoustic amplitudes to compensate for attenuation due to scatter and absorption [6,10]. The current state-of-the-art of ultrasonic testing is the use of dry point contact transducers that are pressed onto the specimen surface and can generate either longitudinal or shear waves into the specimen [2].…”

Section: Introductionmentioning

confidence: 99%

OsciCheck: A Novel Fluidic Transducer for Air-Coupled Ultrasonic Measurements

Bühling¹,

Maack²,

Strangfeld³

2022

eJNDT

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Ultrasonic measurement technology has become indispensable in NDT-CE. Air-coupled ultrasonic (ACU) measurement techniques promise to reduce measurement time. However, the signal quality suffers from large specific impedance mismatch at the transducer-air and air-specimen interface. Additionally, large pressure amplitudes are necessary for the penetration depth required in NDT-CE applications. To address the specific requirements of ultrasonic testing in NDT-CE, a robust ACU transducer was developed, that generates ultrasound by quickly switching a pressurized air flow. The simple design of the fluidic transducer makes the device maintenance free and resilient against harsh environmental conditions. Since the signal is generated by aeroacoustics, there is no specific impedance mismatch between the transducer and the surrounding air. The ultrasonic signal exhibits frequencies in the 30-60 kHz range and is therefore well suited to penetrate heterogenous materials such as concrete. This contribution gives an introduction in the working principle and signal characteristics of the fluidic transducer. Its application on different materials is validated. A detailed outlook is given to discuss the future potential of fluidic ultrasonic actuators.

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Numerical investigation of the effect of heterogeneity on the attenuation of shear waves in concrete

Cited by 26 publications

References 28 publications

Design and Performance Analysis of an Ultrasonic System for Health Monitoring of Concrete Structure

Design and Performance Analysis of an Ultrasonic System for Health Monitoring of Concrete Structure

Experimental Validation of the Attenuation Properties in the Sonic Range of Metaconcrete Containing Two Types of Resonant Inclusions

OsciCheck: A Novel Fluidic Transducer for Air-Coupled Ultrasonic Measurements

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