scholarly journals Features and results of assessment the thermal conductivity of building materials and products by the active method of thermal non-destructive testing

2020 ◽  
Vol 220 ◽  
pp. 01053
Author(s):  
Denis Karpov ◽  
Mikhail Pavlov ◽  
Liliya Mukhametova ◽  
Anton A. Mikhin
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Test Object ◽  
Building Materials ◽  
Thermal Control ◽  
External Source ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Operational Conditions ◽  
Non Destructive

Thermal control (passive and active) is a non-destructive testing method. During passive thermal control, the test object is characterized by a temperature field formed during its operation. In active thermal control, the test object is additionally thermally stimulated. This technique is widely used in various areas of construction, energy, mechanical engineering, transport. This paper proposes a variant of active thermal non-destructive assessment of the thermal conductivity coefficient of building materials and products on the example of a fragment of a building structure made of silicate bricks. The test object is subjected to thermal stimulation by an external source of thermal energy before reaching a steady-state thermal regime. Thermography of the test object surfaces is carried out. The average integral temperatures of surfaces or individual sections of the test object are calculated. The coefficient of thermal conductivity of the test object is determined, which is used to calculate its thermal resistance (resistance to heat transfer). After that, the coefficient of heat transfer is calculated. The method was implemented in laboratory conditions. It can be used in natural and operational conditions for accurate and quick determination of the key thermophysical properties of building materials and products.

scholarly journals THE ACTIVE METHOD OF CONTROL THE THERMAL CONDUCTIVITY OF BUILDING MATERIALS AND PRODUCTS

2019 ◽  
Vol 4 (7) ◽  
pp. 57-62
Author(s):  
Д. Карпов ◽  
Denis Karpov
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Test Object ◽  
Building Materials ◽  
Thermal Control ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Transfer Resistance ◽  
Non Destructive ◽  
Controlled Object

Thermal control refers to non-destructive testing methods. There are passive and active thermal non-destructive testing. With passive thermal control, the test object is characterized by a temperature field formed during its operation. With active thermal control, an additional source of thermal stimulation of the controlled object is used. Thermal control is widely used in various sectors of construction, energy, engineering and transport. The paper proposes a variant of active thermal non-destructive control of thermal conductivity coefficient of building materials and products on the example of a fragment of a building structure made of silicate bricks. The controlled object is subjected to thermal stimulation by an external source of thermal energy until the fixed thermal regime. Thermography of the test object surfaces is performed. The average values of surfaces temperature or individual sections of controlled object are calculated. The heat equation determines a controlled parameter - the heat coefficient of the object under control. The thermal resistance (heat transfer resistance) of the controlled object is calculated with a known coefficient of thermal conductivity. The heat transfer coefficient is calculated with a known coefficient of thermal resistance (heat transfer resistance). The method is implemented in the laboratory. It can be used in field and operating conditions for accurate and rapid determination of the key thermal properties of building materials and products.

High Resolution 3D modelling of Cylinder shape bodies applied to 1000 ancient BC columns

2020 ◽  
Author(s):  
Giuseppe Casula ◽  
Silvana Fais ◽  
Francesco Cuccuru ◽  
Maria Giovanna Bianchi ◽  
Paola Ligas
Keyword(s):  
High Resolution ◽  
Building Materials ◽  
Laser Scanner ◽  
3D Modelling ◽  
Ultrasonic Tomography ◽  
Terrestrial Laser Scanner ◽  
Non Destructive Testing ◽  
Historical Buildings ◽  
Destructive Testing ◽  
Non Destructive

<p>A multi-technique high resolution 3D modelling is described here aimed at the investigation of the state of conservation of carbonate columns of the 1000 BC ancient church of Buon Camino located in the homonymous district of the town of Cagliari (Italy).</p><p>The integrated application of different Non-Destructive Testing (NDT) diagnostic methods is of paramount importance to locate damaged parts of the building material of artefacts of historical buildings and to plan their restoration.</p><p>In this study a multi-step procedure was applied starting with a high resolution 3D modelling performed with the aid of Structure from Motion (SfM) Photogrammetry and Terrestrial Laser Scanner (TLS) methodologies. For this delicate task we operated simultaneously a Nikon D-5300 digital Reflex 24.2 Mega pixel Camera and a Leica HDS-6200 Terrestrial Laser Scanner. Subsequently, starting from the information detected with the above methods deeper material diagnostics was performed by means of high resolution 3D ultrasonic tomography aimed at the capillary definition of the elastic properties in the inner parts of the building materials. Measurements of longitudinal wave velocity from ultrasonic data were performed using the transmission method, namely two piezoelectric transducers coupled on the opposite sides of the investigated columns. The ultrasonic data acquisition was planned designing an optimal survey and providing a very good spatial coverage of the investigated columns. The columns were then criss-crossed by a large number of ray paths forming a dense 3D net. The SIRT (Simultaneous Iterative Reconstruction Tomography) algorithm was used to produce the 3D rendering of the velocity distribution inside the investigated columns. With this method the damaged parts were located and it was possible to distinguish them from the unaltered areas. The information on the superficial material conditions obtained by SfM and TLS techniques were compared and integrated with the information of the inner materials obtained by 3D ultrasonic tomography.</p><p>The results of the above non invasive geophysical techniques have been interpreted in the light of the different textural and petrophysical features of the study carbonate building materials. The study of the main textural features, such as the relationship between bioclasts, carbonate matrix, or that of the cement and petrophysical characteristics such as the nature and distribution of porosity were found to be of fundamental importance in the interpretation of the geophysical data (e.g. TLS reflectance and longitudinal acoustic wave propagation). Therefore a detailed analysis of the textures and pore microstructure were carried out from petrographic thin-sections in Optical and Scanning Electron Microscopy (OM/SEM). The final result of our multi-step-technique integrated methodology is a sophisticated 3D model with a high resolution 3D image representing the internal and external parts of the investigated columns in order to account for their static load resistance and possibly plan their conservation and restoration. The described procedure can also be applied to other cases in which a diagnosis is needed of the state of conservation of the variously shaped, layered-stones and composed artefacts typical of ancient historical buildings.</p><p>Key words: 3D Modelling, 3D Ultrasonic Tomography, Terrestrial Laser Scanner, SfM Photogrammetry, Non-Destructive Testing, Diagnostic, Ancient Columns, Stones</p>

Design of Methodology for Non-Destructive Testing of Steel-Reinforced-Fiber-Concrete

2016 ◽  
Vol 714 ◽  
pp. 179-185 ◽  
Author(s):  
Tereza Komárková
Keyword(s):  
Building Materials ◽  
Construction Material ◽  
Measuring Instruments ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Steel Fibres ◽  
Steel Fibre Reinforced Concrete ◽  
Fibre Concrete ◽  
Reinforced Fiber ◽  
Non Destructive

Measuring instruments used for non-destructive testing of structures thanks to advances in electronics and electrical engineering are still more frequently applied. Among the building materials with which the ability to perform quality control using non-destructive testing methods would be most welcome is indisputably steel reinforced fibre concrete (SFRC). The paper deals with the design of new methods and methodologies that enable determination of the concentration and orientation of steel fibres in steel fibre reinforced concrete. Especially the distribution of steel fibres in concrete is the quintessential aspect of this construction material. Initial results of experiments have demonstrated the applicability of the proposed methods and methodologies and the objective of the article is to introduce it to the scientific community.

Ультразвуковой контроль дефектов металлических изделий сложной формы

2021 ◽  
pp. 31-36
Author(s):  
В.В. Ларионов ◽  
А.М. Лидер ◽  
Д.О. Долматов ◽  
Д.А. Седнев
Keyword(s):  
Test Object ◽  
Degrees Of Freedom ◽  
Surface Profile ◽  
Ultrasonic Waves ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Six Degrees Of Freedom ◽  
Wide Range ◽  
Manufactured Products ◽  
Non Destructive

Nowadays, automation is an actual issue in the development of methods and equipment for ultrasonic non-destructive testing. The conditions of modern industrial production require the development and application the automated testing equipment which is versatile to a wide range of manufactured products, which can have a complex shape. In this paper, we propose a technique for ultrasonic testing of complex-shaped objects. Such technique implies the application of six degrees of freedom robotic manipulators to ensure the required refraction angle of ultrasonic waves into the test object at each measuring position. The trajectory of the robot movement during scanning is provided by restoring the surface profile of the test object using optical profilometry and determining the location of the test object relative to the robotic manipulator using a probe tip. Within the framework of this work, the effectiveness of the developed technology is verified experimentally.

MICROWAVE HEATING IN THE SYSTEM OF NON-DESTRUCTIVE TESTING OF THE THERMOPHYSICAL CHARACTERISTICS OF BUILDING MATERIALS AND PRODUCTS

2020 ◽  
pp. 38-43
Author(s):  
S. A. Mordasov ◽  
A. P. Negulyaeva ◽  
V. N. Chernyshov
Keyword(s):  
Building Materials ◽  
Control Point ◽  
Measuring System ◽  
Non Destructive Testing ◽  
Thermophysical Characteristics ◽  
Destructive Testing ◽  
Information Measuring System ◽  
Pulse Form ◽  
Non Destructive ◽  
Frequency Pulse

A new method is proposed for determining the thermophysical characteristics (thermal conductivity and thermal diffusivity) of building materials and products according to the results of measurements at two points in time of the surface temperature of the object under study, which is subjected to pulsed thermal effect from a given power focused into the line of microwave radiation. In the proposed method, the number of pulses and their repetition rate are set adaptively when the steady-state excess temperature is reached at the control point with two predetermined values at two points in time, which allows non-destructive testing of the studied objects, since the preset temperature values are taken 20…30 % less temperature thermal decomposition of the studied materials, as well as receive information in the frequency-pulse form, which increases the accuracy of the control results and noise method To implement the proposed method, a microprocessor-based information-measuring system has been developed that has experimentally confirmed the efficiency of the method and the correctness of its theoretical conclusions.

scholarly journals Terrestrial Laser Scanner as a Tool for Assessment of Saturation and Moisture Movement in Building Materials

2018 ◽  
Author(s):  
Czesław Suchocki ◽  
Jacek Katzer ◽  
Jacek Rapiński
Keyword(s):  
Structural Engineering ◽  
Building Materials ◽  
Laser Scanner ◽  
Research Programme ◽  
Terrestrial Laser Scanner ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Moisture Movement ◽  
Existing Structures ◽  
Non Destructive

Non Destructive Testing (NDT) is a key element of modern civil engineering. It is especially important in civil and structural engineering helping both in quality control of produced elements and technical assessments of existing structures. Existing NDT methods are being continuously improved and new methods are developed or adopted from different engineering fields. Terrestrial Laser Scanner (TLS) method which is commonly used for geodetic applications has a great potential to be successfully harnessed in civil and structural engineering. TLS can be used for remote sensing of saturation of building materials. A research programme was prepared in order to prove this concept. Specimens representing most popular European building materials were scanned using TLS. Tested specimens were in different saturation states including capillary rising saturation. The saturation assessment was based on differences of values of intensity. The concept proved to be feasible and technically realistic.

Rebound Hammer Tests of Calcium Silicate Bricks – Effects of Internal Compressive Stress on Measurement Results

2014 ◽  
Vol 595 ◽  
pp. 155-158 ◽  
Author(s):  
Jiří Brožovský
Keyword(s):  
Compressive Strength ◽  
Compressive Stress ◽  
Calcium Silicate ◽  
Building Materials ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Measurement Results ◽  
Rebound Number ◽  
Non Destructive ◽  
Calibration Relations

The rebound hammers of the Schmidt system belong among the non-destructive testing methods that are used for determining compressive strength of building materials, most often concrete and rocks. Calibration relations between the rebound number and compressive strength must be available to determine the compressive strength. Calibration relations are determined on the basis of destructive and non-destructive tests of test specimens. This paper deals with the effects of internal compressive stress in calcium silicate bricks on measurement results obtained using the L-type Schmidt hammer. Based on the obtained information, in order to process calibration relations, it is recommended to apply such force to the test specimens, which corresponds to the internal compressive stress 10-15% of the final compressive strength. We do not recommend measuring on firmly supported bricks only.

scholarly journals Non-Destructive Testing of Materials in Civil Engineering

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3237 ◽  
Author(s):  
Krzysztof Schabowicz
Keyword(s):  
Building Materials ◽  
Civil Engineering ◽  
Current Trend ◽  
Building Structures ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Acoustic Methods ◽  
Recent Developments ◽  
Concrete Elements ◽  
Non Destructive

This issue was proposed and organized as a means to present recent developments in the field of non-destructive testing of materials in civil engineering. For this reason, the articles highlighted in this editorial relate to different aspects of non-destructive testing of different materials in civil engineering, from building materials to building structures. The current trend in the development of non-destructive testing of materials in civil engineering is mainly concerned with the detection of flaws and defects in concrete elements and structures, and acoustic methods predominate in this field. As in medicine, the trend is towards designing test equipment that allows one to obtain a picture of the inside of the tested element and materials. Interesting results with significance for building practices were obtained.

scholarly journals Uncertainty Analysis of Infrared Thermography in Convective Heat Transfer

Volume 1 ◽  
2004 ◽  
Author(s):  
Nelson K. Akafuah ◽  
Carsie A. Hall ◽  
Ting Wang
Keyword(s):  
Heat Transfer ◽  
Temperature Measurement ◽  
Convective Heat Transfer ◽  
Infrared Thermography ◽  
Convective Heat ◽  
Infrared Camera ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Test Plate ◽  
Non Destructive

Infrared thermography is the preferred choice in many industrial processes for thermal diagnostics, condition monitoring, and non-destructive testing. However, the inherent uncertainty of surface emissivity affects the accuracy of temperature measurement by infrared thermography. In this paper a comprehensive experimental investigation was conducted to assess the uncertainty of infrared thermography in convective heat transfer. Four convective heat transfer conditions, including natural and forced convection on a flat plate, were studied. A composite test plate was constructed with an embedded heater and thermocouples. The thermocouples were used as references to compare with measurements by the infrared camera. The results indicate that the uncertainty of temperature measurement is about 4°F (2.7% of the wall-to-ambient temperature difference) with the largest uncertainty being contributed by calibration of the infrared camera. The uncertainty of the heat transfer coefficient is 4.2% which is largely contributed by wall temperature measurement.

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