scholarly journals Permittivity measurement of cementitious materials and constituents with an open-ended coaxial probe: combination of experimental data, numerical modelling and a capacitive model

2019 ◽  
Vol 4 ◽  
pp. 39-48 ◽  
Author(s):  
Vincent Guihard ◽  
Frédéric Taillade ◽  
Jean-Paul Balayssac ◽  
Barthélémy Steck ◽  
Julien Sanahuja
Keyword(s):  
Cementitious Materials ◽  
Reference Plane ◽  
Non Destructive Testing ◽  
Calibration Technique ◽  
Destructive Testing ◽  
Near Surface ◽  
Measuring Device ◽  
Coaxial Probes ◽  
Non Destructive ◽  
Coaxial Probe

The study presents the development of a new two-dimensional FEM numerical model describing the operation of two large open-ended coaxial probes designed to investigate the permittivity of concrete, and its constituents. This numerical simulation, combined with a capacitive approach describing the behaviour of the probes, enabled to prove the suitability of such device to determine the permittivity of dispersive dielectrics. Finding back the permittivity of a specified material by calculation of the S parameters, change of the reference plane and use of the capacitive model is the key to the proof. Measurements performed onto different materials show good similarities with the numerical simulations. Special considerations are mentioned concerning the size of the probe and its ability to measure the permittivity of heterogeneous materials made of large inclusions. Combination of such numerical tool and measuring device can be used as a non-destructive testing technique to assess the near surface permittivity of concrete structures or as a calibration technique for GPR measurements.

scholarly journals Effectiveness of the Reverse Bending and Straightening Tests in Detecting Laminations in Wires for Civil Engineering Applications

2013 ◽  
Vol 59 (4) ◽  
pp. 423-439 ◽  
Author(s):  
K.K. Adewole ◽  
S.J. Bull
Keyword(s):  
Civil Engineering ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Engineering Applications ◽  
Near Surface ◽  
Fe Simulations ◽  
Pass Through ◽  
Non Destructive

Abstract The reverse bending and straightening test is conducted on wires used for civil engineering applications to detect laminations which can pose a threat to the integrity of the wires. The FE simulations of the reverse bending and straightening of wires with laminations revealed that the reverse bending and straightening test is only effective in revealing or detecting near-surface laminations with lengths from 25mm located up to 30% of the wire’s thickness and may not be an effective test to detect mid-thickness, near-mid-thickness, and short near-surface laminations with lengths below 15mm. This is because wires with mid-thickness, near-mid-thickness and short nearsurface laminations will pass through the reverse bending and straightening procedures without fracturing and therefore mid-thickness, near-mid-thickness and short near-surface laminations may go undetected. Consequently, other in-line non destructive testing methods might have to be used to detect mid-thickness, near-mid-thickness and short near-surface laminations in the wires.

Non-destructive testing of aerospace composite materials using digital shearography

1998 ◽  
Vol 212 (1) ◽  
pp. 21-30 ◽  
Author(s):  
W Steinchen ◽  
L Yang ◽  
G Kupfer ◽  
P Mäckel
Keyword(s):  
Large Scale ◽  
Laser Interferometry ◽  
Honeycomb Structure ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Measuring Device ◽  
Large Scale Structures ◽  
Reinforced Plastics ◽  
Digital Imaging Processing ◽  
Non Destructive

Digital shearography, a laser interferometry technique in conjunction with the digital imaging processing, has the potential for identifying defects both in small- and large-scale structures. This paper will focus on the recent development of digital shearography for non-destructive testing (NDT). With the improvement of the measuring methods and the development of a small and mobile measuring device in conjunction with a user-guided program, Shearwin, this laser inspection technique can be used easily in the environment of fieldwork. A few examples show its application in the aerospace industry for NDT of composites, e.g. GLARE panel, honeycomb structure and glass (or carbon)-fibre-reinforced plastics, etc.

scholarly journals Non-destructive Testing of Wooden Elements

2021 ◽  
Vol 1203 (3) ◽  
pp. 032058
Author(s):  
Monika Zielińska ◽  
Magdalena Rucka
Keyword(s):  
Surface Defects ◽  
Test Methods ◽  
Ultrasonic Tomography ◽  
Test Results ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Near Surface ◽  
Thermal Techniques ◽  
Ground Penetrating ◽  
Non Destructive

Abstract Examining the condition of wooden elements is crucial from the perspective of proper structure performance. If the deterioration in the internal wood condition, which displays no symptoms visible from the outside, is detected, the further spread of the deterioration can be prevented. Test results often point to the necessity of conducting repairs and, renovations, replacing the structure of wooden beams, or even substituting a significant part of the structure. To achieve acceptable results, test methods should take into account the anisotropic nature of wood, which includes the shape of annual rings, as well as the location of the core in crosssection. To adopt methods based on physical effects, profound knowledge of wood physics is needed, particularly of interdependence. Apart from simple tests such as a visual inspection or tapping that are used to determine near-surface defects, non-destructive testing (NDT) plays an important role in the process. This paper presents the methods of non-destructive testing of wooden elements. These methods include tests conducted with ground penetrating radar (GPR), thermal techniques, microwaves, acoustic emission, ultrasonic tomography, and X-ray tomography. The paper summarises the use of non-destructive methods, indicating their advantages, disadvantages as well as some limitations.

scholarly journals Detection of near-surface reinforcement in concrete components with ultrasound

2018 ◽  
Vol 199 ◽  
pp. 06007
Author(s):  
Sarah Vonk ◽  
Alexander Taffe
Keyword(s):  
Prestressed Concrete ◽  
Concrete Cover ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Near Surface ◽  
Measuring Devices ◽  
Inductive Methods ◽  
Surface Reinforcement ◽  
The University ◽  
Non Destructive

Ultrasonic testing of concrete has grown in importance considerably in recent years in non-destructive testing in civil engineering (NDT-CE). In the past, the main focus was on the imaging of the internal construction of steel and prestressed concrete components. On the other hand, comparatively little attention was paid to the location of near-surface reinforcement and concrete cover measurement. In this research, it is shown to what extent ultrasound is suitable for the detection of near-surface reinforcement in addition to magnetic inductive methods. The measurements were carried out with the newly developed Pundit 250 Array from the company Proceq and with the measuring devices of the company Acsys, the A1220 Monolith and the A1040 Mira. The ultrasound data was analysed with the vendor-independent software InterSAFT of the University of Kassel. Systematic investigations were carried out on test specimens with a variety on the concrete cover, the diameter of the reinforcement and the reinforcement ratio in the form of mesh reinforcement close to the surface. The detectability and accuracy of the concrete cover were set in relation to the concrete cover, wavelength and reinforcement diameter, with the result that more detailed rules for the detection of reinforcement are formulated for the user, instead of the known λ/2-criterion.

Thermoelectric Method of Plastic Deformation Detection

2018 ◽  
Vol 938 ◽  
pp. 112-118 ◽  
Author(s):  
A.I. Soldatov ◽  
A.A. Soldatov ◽  
P.V. Sorokin ◽  
A.A. Abouellail ◽  
M.A. Kostina
Keyword(s):  
Plastic Deformation ◽  
Thermoelectric Power ◽  
Power Measurement ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Measuring Device ◽  
Thermoelectric Method ◽  
Maximum Change ◽  
Thermoelectric Power Measurement ◽  
Non Destructive

The paper presents an approach of non-destructive testing of plastic deformation of metals and alloys by measuring the differential thermoelectric power. Using the developed measuring device for this purpose, measurements of thermoelectric power were performed on several types of steels that are used in the manufacture of product pipelines. Incisions were made on the surface of the testes objects, for the purpose of experimental detection of the place of plastic deformation. In the process of stretching, thermoelectric power was measured at and near the place of the proposed plastic deformation. During the process of stretching the sample, the decrease in thermoelectric power measurement occurs almost linearly. The maximum change in the thermoelectric power measurement of the tested object was observe before the rapture discontinuity.

Thermographic non-destructive testing damage detection for metals and cementitious materials

2000 ◽  
Vol 48 (1) ◽  
pp. 33-43 ◽  
Author(s):  
J K C Shih ◽  
R Delpak ◽  
C W Hu ◽  
P Plassmann ◽  
A Wawrzynek ◽  
...  
Keyword(s):  
Damage Detection ◽  
Cementitious Materials ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive

scholarly journals Magnetic Flux Leakage Course of Inner Defects and Its Detectable Depth

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Jianbo Wu ◽  
Wenqiang Wu ◽  
Erlong Li ◽  
Yihua Kang
Keyword(s):  
Magnetic Flux ◽  
Steel Structure ◽  
High Sensitivity ◽  
Magnetic Flux Leakage ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Near Surface ◽  
Testing Method ◽  
Non Destructive ◽  
Flux Leakage

AbstractAs a promising non-destructive testing (NDT) method, magnetic flux leakage (MFL) testing has been widely used for steel structure inspection. However, MFL testing still faces a great challenge to detect inner defects. Existing MFL course researches mainly focus on surface-breaking defects while that of inner defects is overlooked. In the paper, MFL course of inner defects is investigated by building magnetic circuit models, performing numerical simulations, and conducting MFL experiments. It is found that the near-surface wall has an enhancing effect on the MFL course due to higher permeability of steel than that of air. Further, a high-sensitivity MFL testing method consisting of Helmholtz coil magnetization and induction coil with a high permeability core is proposed to increase the detectable depth of inner defects. Experimental results show that inner defects with buried depth up to 80.0 mm can be detected, suggesting that the proposed MFL method has the potential to detect deeply-buried defects and has a promising future in the field of NDT.

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