scholarly journals Damage Detection of Asphalt Concrete Using Piezo-Ultrasonic Wave Technology

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 443 ◽  
Author(s):  
Wen-hao Pan ◽  
Xu-dong Sun ◽  
Li-mei Wu ◽  
Kai-kai Yang ◽  
Ning Tang
Keyword(s):  
Damage Detection ◽  
Ultrasonic Wave ◽  
Ultrasonic Velocity ◽  
Asphalt Concrete ◽  
Ultrasonic Waves ◽  
Bending Test ◽  
Measured Velocity ◽  
Three Point Bending ◽  
Wave Technology ◽  
Wave Velocities

Asphalt concrete has been widely used in road engineering as a surface material. Meanwhile, ultrasonic testing technology has also been developed rapidly. Aiming to evaluate the feasibility of the ultrasonic wave method, the present work reports a laboratory investigation on damage detection of asphalt concrete using piezo-ultrasonic wave technology. The gradation of AC-13 was selected and prepared based on the Marshall’s design. The ultrasonic wave velocities of samples were tested with different environmental conditions firstly. After that, the samples were destroyed into two types, one was drilled and the other was grooved. And the ultrasonic wave velocities of pretreated samples were tested again. Furthermore, the relationship between velocity and damaged process was evaluated based on three point bending test. The test results indicated that piezoelectric ultrasonic wave is a promising technology for damage detection of asphalt concrete with considerable benefits. The ultrasonic velocity decreases with the voidage increases. In a saturated water environment, the measured velocity of ultrasonic wave increased. In a dry environment (50 °C), the velocity the ultrasonic waves increased too. After two freeze-thaw cycles, the voidage increased and the ultrasonic velocity decreased gradually. After factitious damage, the wave must travel through or most likely around the damage, the ultrasonic velocity decreased. During the process of three point bending test, the ultrasonic velocity increased firstly and then decreased slowly until it entered into a steady phase. At last the velocity of ultrasonic wave decreased rapidly. In addition, the errors of the results under different test conditions need to be further studied.

Effect of Loading Rate on the Properties of Asphalt Concrete Using Three-Point Bending Test

2015 ◽  
Vol 1096 ◽  
pp. 553-556
Author(s):  
Islam Md Rashadul ◽  
Ahmad Mohiuddin ◽  
A. Tarefder Rafiqul
Keyword(s):  
Asphalt Concrete ◽  
Room Temperature ◽  
Loading Rate ◽  
Failure Stress ◽  
Bending Test ◽  
Initial Stiffness ◽  
Slow Cooling ◽  
Three Point Bending ◽  
Bending Loading ◽  
Strain Increase

This study investigates the effect of loading rate on Asphalt Concrete (AC) in the laboratory using Three-Point Bending test. As a first step, beam samples were prepared using kneading compactor and final shape of the sample was obtained by laboratory saw. The samples were then subjected to bending loading at different deformation rates at room temperature of 20 °C. The initial stiffness, failure stress (tensile strength) and failure strain were monitored. Results show that the stiffness and the failure stress-strain increase with the increase in loading rate. The findings of the study are expected to be useful to understand the performance of AC due to slow loading such as slow cooling.

Investigation of the Mechanical Properties of Bone Using Ultrasound

1989 ◽  
Vol 203 (1) ◽  
pp. 61-63 ◽  
Author(s):  
P J Gill ◽  
G Kernohan ◽  
I N Mawhinney ◽  
R A B Mollan ◽  
R McIlhagger
Keyword(s):  
Mechanical Properties ◽  
Ultrasonic Velocity ◽  
Mechanical Performance ◽  
Zealand White Rabbit ◽  
Bending Test ◽  
Velocity Measurements ◽  
Bending Properties ◽  
Constant Energy ◽  
Three Point Bending ◽  
New Zealand White Rabbit

This paper examines the serial use of ultrasonic velocity measurement to monitor fracture healing. New Zealand White rabbit tibiae were fractured using a constant-energy technique and the ultrasonic velocity along the bone measured in animals sacrificed at 16 day intervals up to 96 days from fracture. In parallel with these measurements the mechanical performance of the healed tibiae were determined using a three-point bending test. Regression analysis failed to show a sufficiently good correlation between ultrasonic velocity measurements and the bending properties of healing fractures for the method to be of use clinically.

Damage Detection in CFRP Bonded Structures by Using Fiber Bragg Grating Sensors as Ultrasonic Wave Receivers

2007 ◽  
Vol 334-335 ◽  
pp. 1137-1140
Author(s):  
Nobuo Takeda ◽  
Y. Okabe ◽  
J. Kuwahara ◽  
Toshimichi Ogisu ◽  
Seiji Kojima
Keyword(s):  
Wavelet Transform ◽  
Damage Detection ◽  
Fiber Bragg Grating ◽  
Correlation Coefficient ◽  
Ultrasonic Wave ◽  
Detection System ◽  
Damage Index ◽  
Adhesive Layer ◽  
Ultrasonic Waves ◽  
Bragg Grating

The authors developed a damage detection system that generates ultrasonic waves with a piezo-ceramic actuator and receives them by a fiber Bragg grating (FBG) sensor. In this research, this system was applied to evaluate debonding progress in CFRP skin/stringer bonded structures. FBG sensors were bonded on the stringer or embedded in the adhesive layer. Then, ultrasonic wave at 300kHz was propagated through the debonded region, and the wavelet transform was applied to the received waveform. After that, a new damage indexand a correlation coefficient were calculated from the distribution of the wavelet transform coefficient. As a result, the damage index increased and the correlation coefficient decreased with an increase in the debonded area. Hence the length of the debonding between the skin and the stringer could be well evaluated.

scholarly journals Additive Manufacturing-Based In Situ Consolidation of Continuous Carbon Fibre-Reinforced Polycarbonate

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2450
Author(s):  
Andreas Borowski ◽  
Christian Vogel ◽  
Thomas Behnisch ◽  
Vinzenz Geske ◽  
Maik Gude ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Carbon Fibre ◽  
Bending Test ◽  
Thermoplastic Composites ◽  
Experimental Investigations ◽  
Material Structure ◽  
Three Point Bending ◽  
Continuous Fibre ◽  
Local Material

Continuous carbon fibre-reinforced thermoplastic composites have convincing anisotropic properties, which can be used to strengthen structural components in a local, variable and efficient way. In this study, an additive manufacturing (AM) process is introduced to fabricate in situ consolidated continuous fibre-reinforced polycarbonate. Specimens with three different nozzle temperatures were in situ consolidated and tested in a three-point bending test. Computed tomography (CT) is used for a detailed analysis of the local material structure and resulting material porosity, thus the results can be put into context with process parameters. In addition, a highly curved test structure was fabricated that demonstrates the limits of the process and dependent fibre strand folding behaviours. These experimental investigations present the potential and the challenges of additive manufacturing-based in situ consolidated continuous fibre-reinforced polycarbonate.

scholarly journals Linear and Nonlinear Normal Interface Stiffness in Dry Rough Surface Contact Measured Using Longitudinal Ultrasonic Waves

2021 ◽  
Vol 11 (12) ◽  
pp. 5720
Author(s):  
Saeid Taghizadeh ◽  
Robert Sean Dwyer-Joyce
Keyword(s):  
Rough Surface ◽  
Contact Pressure ◽  
Ultrasonic Wave ◽  
Bulk Material ◽  
Nonlinear Differential Equations ◽  
Small Deformation ◽  
Ultrasonic Waves ◽  
Solid Contact ◽  
Interfacial Stiffness ◽  
Linear And Nonlinear

When two rough surfaces are loaded together contact occurs at asperity peaks. An interface of solid contact regions and air gaps is formed that is less stiff than the bulk material. The stiffness of a structure thus depends on the interface conditions; this is particularly critical when high stiffness is required, for example in precision systems such as machine tool spindles. The rough surface interface can be modelled as a distributed spring. For small deformation, the spring can be assumed to be linear; whilst for large deformations the spring gets stiffer as the amount of solid contact increases. One method to measure the spring stiffness, both the linear and nonlinear aspect, is by the reflection of ultrasound. An ultrasonic wave causes a perturbation of the contact and the reflection depends on the stiffness of the interface. In most conventional applications, the ultrasonic wave is low power, deformation is small and entirely elastic, and the linear stiffness is measured. However, if a high-powered ultrasonic wave is used, this changes the geometry of the contact and induces nonlinear response. In previous studies through transmission methods were used to measure the nonlinear interfacial stiffness. This approach is inconvenient for the study of machine elements where only one side of the interface is accessible. In this study a reflection method is undertaken, and the results are compared to existing experimental work with through transmission. The variation of both linear and nonlinear interfacial stiffnesses was measured as the nominal contact pressure was increased. In both cases interfacial stiffness was expressed as nonlinear differential equations and solved to deduce the contact pressure-relative surface approach relationships. The relationships derived from linear and nonlinear measurements were similar, indicating the validity of the presented methods.

Effect of Concrete Mixture Composition on Acoustic Emission and Fracture Parameters Obtained from Three-Point Bending Test

2015 ◽  
Vol 1100 ◽  
pp. 152-155
Author(s):  
Libor Topolář ◽  
Hana Šimonová ◽  
Petr Misák
Keyword(s):  
Acoustic Emission ◽  
Bending Test ◽  
Mixture Composition ◽  
Three Point Bending ◽  
Concrete Mixtures ◽  
Fracture Parameters ◽  
Fracture Tests ◽  
Stress Behaviour ◽  
Bending Fracture ◽  
Fracture Processes

This paper reports the analysis of acoustic emission signals captured during three-point bending fracture tests of concrete specimens with different mixture composition. Acoustic emission is an experimental tool well suited for monitoring fracture processes in material. The typical acoustic emission patterns were identified in the acoustic emission records for three different concrete mixtures to further describe the under-the-stress behaviour and failure development. An understanding of microstructure–performance relationships is the key to true understanding of material behaviour. The acoustic emission results are accompanied by fracture parameters determined via evaluation of load versus deflection diagrams recorded during three-point bending fracture tests.

scholarly journals Experimental and Numerical simulation of a Three Point Bending Test of a Stainless Steel Beam

2021 ◽  
Vol 55 ◽  
pp. 1114-1121
Author(s):  
Daniel Jindra ◽  
Zdeněk Kala ◽  
Jiří Kala ◽  
Stanislav Seitl
Keyword(s):  
Numerical Simulation ◽  
Stainless Steel ◽  
Bending Test ◽  
Steel Beam ◽  
Three Point Bending

scholarly journals Fracture and Size Effect of PFRC Specimens Simulated by Using a Trilinear Softening Diagram: A Predictive Approach

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3795
Author(s):  
Fernando Suárez ◽  
Jaime C. Gálvez ◽  
Marcos G. Alberti ◽  
Alejandro Enfedaque
Keyword(s):  
Reinforced Concrete ◽  
Size Effect ◽  
A Priori ◽  
Plain Concrete ◽  
Specimen Size ◽  
Bending Test ◽  
Orientation Factor ◽  
Fibre Reinforced Concrete ◽  
Softening Function ◽  
Three Point Bending

The size effect on plain concrete specimens is well known and can be correctly captured when performing numerical simulations by using a well characterised softening function. Nevertheless, in the case of polyolefin-fibre-reinforced concrete (PFRC), this is not directly applicable, since using only diagram cannot capture the material behaviour on elements with different sizes due to dependence of the orientation factor of the fibres with the size of the specimen. In previous works, the use of a trilinear softening diagram proved to be very convenient for reproducing fracture of polyolefin-fibre-reinforced concrete elements, but only if it is previously adapted for each specimen size. In this work, a predictive methodology is used to reproduce fracture of polyolefin-fibre-reinforced concrete specimens of different sizes under three-point bending. Fracture is reproduced by means of a well-known embedded cohesive model, with a trilinear softening function that is defined specifically for each specimen size. The fundamental points of these softening functions are defined a priori by using empirical expressions proposed in past works, based on an extensive experimental background. Therefore, the numerical results are obtained in a predictive manner and then compared with a previous experimental campaign in which PFRC notched specimens of different sizes were tested with a three-point bending test setup, showing that this approach properly captures the size effect, although some values of the fundamental points in the trilinear diagram could be defined more accurately.

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