Influence of Test Specimens Shape on Measurements of Electrical Resistivity of Concrete

2014 ◽  
Vol 634 ◽  
pp. 479-484
Author(s):  
Ronaldo Alves Medeiros ◽  
Maryangela Geimba Lima
Keyword(s):  
Electrical Resistivity ◽  
Service Life ◽  
Low Cost ◽  
Cylindrical Shape ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Use Of Data ◽  
New Models ◽  
Non Destructive ◽  
Execution Technique

The need to insert the durability factor on dimensioning concrete structures has been stimulating the development of new models to predict the service life of those structures. Among those new models, the use of data from Non-Destructive Testing (NDT) is recommended. It is known that electrical resistivity is a parameter related with permeability and, in consequence, with the resistance of the concrete against the intrusion of aggressive agents. Electrical resistivity may be monitored with time by a NDT method, by a low cost and easy execution technique. However, some parameters of this essay need to be further discussed in the literature aiming to standardize this technique. Thus, this study had the goal to verify the influence of test specimen’s shape in measurements of electrical resistivity. In order to that, cylindrical and prismatic test specimens have been molded from a same type of concrete and electrical resistivity was monitored during a period of 120 days. Results show significant differences between the values obtained. Test specimens in cylindrical shape had the higher results. A good correlation between factors was found with R2 higher than 0.94.

Technical Note: Detection of delamination in tyres using eddy currents

1997 ◽  
Vol 211 (1) ◽  
pp. 79-82 ◽  
Author(s):  
X. E. Gros
Keyword(s):  
Eddy Currents ◽  
Structural Integrity ◽  
Low Cost ◽  
Technical Note ◽  
Quality And Safety ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Safety Standards ◽  
Current Testing ◽  
Non Destructive

Non-destructive testing (NDT) is a useful tool to assess the structural integrity of components in order to maintain quality and safety standards. A low-cost electromagnetic technique based on eddy currents induced into a material appeared promising for the inspection of composite materials. Experiments were carried out in order to assess the potential of eddy currents in detecting delamination in rubber tyres. Infrared thermography was used to verify inspection results achieved with eddy currents. Non-destructive examination results are presented in this paper; these confirm that eddy current testing is an economically viable alternative for the inspection of steel reinforced truck tyres.

scholarly journals Motion Analysis of A Low Cost Customized A-Scan Non Destructive Testing Unit

2018 ◽  
Vol 217 ◽  
pp. 04002
Author(s):  
M.N. M. Zukri ◽  
E. A. Bakar
Keyword(s):  
Low Cost ◽  
Research Field ◽  
Small Scale ◽  
Signal Acquisition ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Current Product ◽  
Stepper Motors ◽  
Research And Education ◽  
Non Destructive

This study introduced a new design of a low-cost customized A-scan Non Destructive Testing (NDT) unit using microcontroller-based scanning motion. the scanning unit from previous research has limitations in scanning envelope area and ability of detection. It can only detect large defects. To solve the limitations mentioned above, the purpose of this study is to develop a device with lower cost, more appropriate size of scanning envelop area, and ability to detect internal layer defections. the mechanism of this machine is achieved by using 3 NEMA 17 bipolar stepper motors for the movement of every axis. MATLAB is used in this machine for the purposes of signal acquisition, signal analysis and to control the linear motions. Since this machine is small in size (40cm x 27cm x 72cm), it can be used for small scale testing and analysis. As compared with current product, this machine is more portable and affordable. Thus, it is more convenient in the areas of research and education. the contributions of this machine is providing an affordable machine for advancement research field and enhancement quality inspection in manufacturing industries.

Increasing the Safety of Operation of Industrial Technical Systems from the Composite Materials by Predicting Their Life on the Basis of New Methods of Non-Destructive Control and Deep Neural Networks

2021 ◽  
pp. 7-12
Author(s):  
S.O. Kozelskaya ◽  
Keyword(s):  
Neural Network ◽  
Neural Networks ◽  
Composite Materials ◽  
Service Life ◽  
New Technologies ◽  
Preliminary Training ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
New Methods ◽  
Non Destructive

The problem is considered related to increase of the operational safety of industrial facilities made of composite materials by means of an a priori assessment of the maximum service life. Two tasks are being solved: development of the new methods and means of non-destructive testing allowing to identify the defects that appear in the process of testing products with various loads and in the process of their operation; development of the new methods and means for assessing service life of the products based on the results of non-destructive testing. The first problem is being solved by the development of optical-thermographic non-destructive testing, including the technologies of ultrasonic thermotomography and electric force thermography, which determine the state of the object by dynamic temperature fields and optical control technology based on the fiber-optic sensors that measure the amount of material internal deformation under a force effect on the structure. Solution to the second problem is based on the use of neural network analysis (artificial neural networks) for assessment and prediction of the service life using the results of non-destructive testing with preliminary training of the neural network. An estimate was obtained by the experimental studies related to the error in determining the products service life, which is 12.6 %. The implementation of the proposed approach will allow to create the new technologies for predicting the service life of elements and structures made of composite materials using the results of non-destructive testing, which will provide an additional opportunity for developing practical recommendations on the confirmation or extension of the service life and improvement of safety for structures operation.

Data correlation of non-destructive testing methods to assess asphalt pavement thickness

2020 ◽  
Author(s):  
Christina Plati ◽  
Andreas Loizos ◽  
Konstantinos Gkyrtis
Keyword(s):  
Service Life ◽  
Response Analysis ◽  
Specific Information ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Processing Scheme ◽  
Pavement Evaluation ◽  
Pavement Response ◽  
Surface Deflections ◽  
Non Destructive

<p>Performing structural assessment at any time of asphalt pavements service life is an inherent process within pavement condition assessment. Layers thicknesses are among the major contributors to the overall pavement response and performance. Knowledge of layer thicknesses is imperative for both new and in-service pavements, because thickness data is usually combined with other response indicators (i.e. pavement deflections) in order to perform pavement evaluation during pavements service life. As such, inaccuracies in thickness assessment might result in erroneous response analysis and life expectancy estimation with a detrimental financial impact during maintenance planning.</p><p>Traditionally, layer thicknesses were retrieved through coring or digging test pits. Because of the limitations of these methods (including location-specific information, destructive nature, need for traffic disruptions), the pavement engineering community has consistently drawn its attention to a broadened utilization of advanced Non-Destructive Testing (NDT) systems in order to non-invasively determine the pavement cross-section. The most indicative NDT tool for that purpose is the Ground Penetrating Radar (GPR), which is systematically used for layers thickness evaluation. Within the framework of pavement evaluation processes, GPR is quite often combined with the Falling Weight Deflectometer (FWD), which provides with pavement response indications in terms of surface deflections.</p><p>It is worthwhile mentioning that GPR requires high expertise in order to reliably analyze the collected data and until now, there is none uniquely recognizable and universally accepted signal processing scheme. Supplementary to experienced users and analysts, investments in time and human resources are also needed to make reliable interpretations. Such reasons may potentially discourage related stakeholders from systematic GPR use, especially in cases where there are budgets constraints for the procurement and transportation logistics of multiple expensive equipment.</p><p>In light of the above, related research is pursed in respect to the investigation of the ability of FWD surface deflections indexes to provide with reliable information on the Asphalt Concrete (AC) layer thicknesses. For this purpose, Long-Term Pavement Performance (LTPP) data is analyzed including FWD and GPR data as well as sample coring. A nonlinear regression based relationship is under development that preliminarily exhibits a satisfactory performance both during model fit and model accuracy evaluation. Based on the above framework, it is suggested that the NDT analysis with deflection indexes seems promising in terms of roughly producing AC thickness, thereby balancing constraints at network level.</p>

scholarly journals Relationship of Different Properties from Non-Destructive Testing of Heavy Concrete from Magnetite and Serpentinite

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4288
Author(s):  
Petr Lehner ◽  
Jacek Gołaszewski
Keyword(s):  
Compressive Strength ◽  
Electrical Resistivity ◽  
Diffusion Coefficient ◽  
Modulus Of Elasticity ◽  
Effective Diffusivity ◽  
Radiation Shielding ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Water Penetration ◽  
Non Destructive

Radiation-shielding concrete has been analyzed by several methods of destructive and non-destructive testing (NDT). Concretes made of crushed basalt, magnetite, serpentinite, and two different types of cement (Portland cement CEM I and slag cement CEM III/A) were studied. In this study, we analyzed concrete columns with a height of 1200 mm and a cross-section of 200 × 200 mm2. The top and bottom of the column were analyzed using data from compressive strength, dynamic modulus of elasticity, water penetration, and diffusion coefficients derived from the electrical resistivity test. This article presents the properties of fresh concrete and concrete after two years of setting. It was determined how the different ratios of basalt, magnetite, and serpentinite affect the individual measured parameters. Furthermore, correlation relations between individual resulting values were analyzed. It was observed that compressive strength generally does not correlate with other results. The diffusion coefficient correlated well with density and water penetration. Little or no correlation was observed in the diffusion coefficient with compressive strength and modulus of elasticity. The results of the study make it possible to refine the testing of heavy concretes in terms of electrical resistivity, and point to the possible use of NDT methods. The results also show which composition of heavy concrete is better in terms of effective diffusivity.

scholarly journals Dimensional effect when measuring Martens hardness

2021 ◽  
pp. 128
Author(s):  
Vasyl Moshchenok ◽  
Lyidmila Kostina ◽  
Denis Pluzhnikov
Keyword(s):  
Service Life ◽  
Functional Dependence ◽  
Test Method ◽  
Structural Defects ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
High Productivity ◽  
Dimensional Effect ◽  
Meyer Equation ◽  
Non Destructive

One of the most common methods of non-destructive testing, hardness testing, is used to evaluate the properties of materials. This is due to the ease of measurement and testing of the finished part, which will be used in the future, high productivity of the method, the ability to assess other mechanical properties of the material: elasticity, creep, tensile strength. An important aspect in the study of the hardness using in the range the Berkovich and Vickers indenters, which are more consistent with non-destructive testing, while the methods of Brinell and Rockwell leave quite large deformations, in our opinion, which further promote the development of structural defects and reduce the service life, which are not acceptable in critical products. Due to the improvement of product manufacturability, more and more manufacturers are trying to minimize the size of the part, while increasing their performance by applying a reinforced layer, which, in turn, should seek to reduce the thickness with increased service life. It is also impossible to study the hardness of very small products in the micro range due to the large mismatch between the dimensions of the product under test and the test method. In our opinion, the study of hardness by the Berkovich method in comparison with the Vickers method is more expedient for use with the same physicochemical properties of the material because of a larger scatter of hardness values between the compared methods, although they should be almost the same, with a small difference. An important omission to a certain year was the dimensional effect. Goal. The aim of the study is to assess the nature of the change in hardness with increasing load on the indenter, using the functional dependence of the hardness on the depth of the indenter. For this purpose, it is necessary to establish such connection for an indenter of various geometry. In this regard, we consider it appropriate to check the validity of the Meyer equation, which relates the load to the size of the imprint, for different indenters and materials. Results. When the hardness is calculated according to the Martens scales, the Vickers and Berkovich indenters are applied to the function of the surface area of the working part of the tip. An important factor of the consistency of the results in the increase in hardness is the small effect. The reasons for this can be very negligible. The sizeable effect is significantly infused into the results of increasing hardness, changing from 2,5 to 3,0 folds.

APPLICATION OF DEEP NEURAL NETWORKS BASED ON PALLIATIVE ANALYSIS UNDER CONDITIONS OF INCOMPLETE INFORMATION OF OPTICAL THERMAL AND ELECTRIC NONDESTRUCTIVE TESTING FOR PREDICTION OF THE LIMIT RESOURCE OF OPERATION OF CONSTRUCTION

2021 ◽  
pp. 4-15
Author(s):  
S. O. Kozel'skaya ◽  
D. A. Akimov ◽  
A. S. Andreev ◽  
O. N. Budadin ◽  
V. V. Kotel'nikov
Keyword(s):  
Composite Materials ◽  
Service Life ◽  
Polymer Composite ◽  
Prediction Models ◽  
Test Methods ◽  
Operational Stability ◽  
Polymer Composite Materials ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive

The problem of assessing operational stability and, accordingly, assessing the storage and safe operation periods of objects (for example, load-bearing structural structures made of polymer composite materials (PCM)) has always been one of the most important. At present, this prediction problem is mainly solved on the basis of product testing, as well as a detailed study of the regularities of the physicochemical aging processes occurring in PCM and changes in the physical and mechanical characteristics of products, and the creation on this basis of appropriate test methods and mathematical prediction models. The paper considers the problem of increasing the reliability of assessing the maximum service life of multicomponent structures by constructing predictive models using the results of optical-thermal and electrical non-destructive testing of the state of objects by temperature fields and the value of internal deformation of the material under force on the structure as input information. It is shown that in the case of using logical approaches as a software tool for predicting the ultimate resource of structures made of polymer composite materials, part of the knowledge should be used for reasoning that provides an explanation of the conclusions drawn, since formal logic is of limited applicability, especially in conditions of incomplete or uncertain information. In this case, the solution to the problem becomes the identification and establishment of cause-and-effect relationships. For the tasks of technical assessment of the quality of structures and their service life, the use of such logical conclusions as inductive, deductive and analogous conclusions is impossible, since for their work, they require all information about the diagnosed structure. The use of the proposed method for assessing the service life will allow timely stopping the loading of products with loads and, thus, preventing structural destruction. It should be borne in mind that in order to reliably predict the ultimate service life of complex structures made of composite materials using the proposed method, a set of various input instrumental and subjective information about the structural and operational characteristics of the product is required, including information on intermediate tests, non-destructive testing data. at various stages of manufacturing, design features, stability of parameters during the development process, subjective opinions of specialists, changes in the properties of materials from time to time and loads, etc. Implementation of the proposed approach will allow creating a new generation of test methods and predicting operational stability with an assessment of the limiting service life of elements and structures, which, ultimately, will provide an additional opportunity for developing practical recommendations for confirming or extending the warranty periods of operation and increasing the reliability and safety of operation of structures.

The Use of the Vibroacoustic Method for Monitoring the Technical Condition of Aero Engines with Extended Time between Overhauls

2015 ◽  
Vol 220-221 ◽  
pp. 283-288
Author(s):  
Jarosław Spychała ◽  
Paweł Majewski ◽  
Mariusz Żokowski
Keyword(s):  
Operating System ◽  
Service Life ◽  
Technical Condition ◽  
Extended Time ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Current State ◽  
Turboprop Engine ◽  
Aero Engines ◽  
Non Destructive

The article presents some aspects of several years of work on the use of the vibroacoustic method (Non-Destructive Testing) for assessing a turboprop engine from a trainer aircraft. The functioning engine does not have an operating system for measuring vibration, and therefore the current levels of vibrations and its changes in trends are not known. In order to extend its service life, performing a number of works was required. On the basis of assessing the current state of the engine, opportunities for further exploitation were identified thus developing methodology for evaluating technical condition regarding the whole population. The paper shortly describes the object and equivalent tests on the engine. The article focuses on the methods prepared for extending life between overhauls required for turboprop engines and discusses the results received during their implementation.

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