scholarly journals Calibration of Acoustic Emission Parameters in Relation to the Equilibrium Moisture Content Variations in a Pinus sylvestris Beam

2021 ◽  
Vol 11 (11) ◽  
pp. 5236
Author(s):  
Beatrice Bartolucci ◽  
Francesca Frasca ◽  
Anna Maria Siani ◽  
Chiara Bertolin
Keyword(s):  
Acoustic Emission ◽  
Moisture Content ◽  
Pinus Sylvestris ◽  
Equilibrium Moisture Content ◽  
Testing Machine ◽  
Acoustic Emissions ◽  
Image Correlation ◽  
Experimental Procedure ◽  
Non Destructive

Under constant temperature conditions, air relative humidity variations affect hygroscopic objects, such as wood, modifying their moisture content and provoking, at low values, damages and fractures. The parameters (amplitude, counts, and energy) derived from the acoustic emission non-destructive technique are calibrated with respect to equilibrium moisture content values using 14 samplings of Pinus sylvestris. The experimental procedure uses multi-technique approaches involving a universal testing machine, digital image correlation, and acoustic emissions, and notes that the three parameters of acoustic emission strictly depend on the equilibrium moisture content. For a better interpretation, a statistical approach is applied to model the equilibrium moisture content variations radially and longitudinally. Amplitude, counts, and energy are calibrated as a function of the equilibrium moisture content, indicating that all three parameters are necessary to have an integral vision of the conservation of a wooden material. Moreover, the shape of the macro-fractures that occur at the surface can be associated with the level of moisture or dryness of the sample. Finally, the proposed method can be used in situ because, through acoustic emission monitoring, it is possible to quantify the fingerprint of the state of conservation of a material.

scholarly journals Challenges and Accomplishments in Mechanical Testing Instrumented by In Situ Techniques: Infrared Thermography, Digital Image Correlation, and Acoustic Emission

2021 ◽  
Vol 11 (15) ◽  
pp. 6718
Author(s):  
Aleksander Sendrowicz ◽  
Aleksander Omholt Myhre ◽  
Seweryn Witold Wierdak ◽  
Alexei Vinogradov
Keyword(s):  
Acoustic Emission ◽  
Digital Image Correlation ◽  
Mechanical Testing ◽  
Digital Image ◽  
Image Correlation ◽  
Deformation And Fracture ◽  
Fracture Of Materials ◽  
Non Destructive ◽  
Fracture Processes

A current trend in mechanical testing technologies is to equip researchers and industrial practitioners with the facilities for non-destructive characterisation of the deformation and fracture processes occurring on different scales. The synergistic effect of such a combination of destructive and non-destructive techniques both widens and deepens existing knowledge in the field of plasticity and fracture of materials and provides the feedback sought to develop new non-destructive testing approaches and in situ monitoring techniques with enhanced reliability, accuracy and a wider scope of applications. The macroscopic standardised mechanical testing is still dominant in the research laboratories and industrial sector worldwide. The present paper reviews multiple challenges commonly faced by experimentalists, aiming at enhancing the capability of conventional mechanical testing by a combination of contemporary infrared thermography (IRT), rapid video imaging (RVI) with non-contact strain mapping possibilities enabled by the digital image correlation (DIC) method, and the acoustic emission (AE) technique providing unbeatable temporal resolution of the stochastic defect dynamics under load. Practical recommendations to address these challenges are outlined. A versatile experimental setup uniting the unique competencies of all named techniques is described alone with the fascinating possibilities it offers for the comprehensive characterisation of damage accumulation during plastic deformation and fracture of materials. The developed toolbox comprising practical hardware and software solutions brings together measuring technologies, data, and processing in a single place. The proposed methodology focuses on the characterisation of the thermodynamics, kinematics and dynamics of the deformation and fracture processes occurring on different spatial and temporal scales. The capacity of the proposed combination is illustrated using preliminary results on the tensile and fatigue behaviour of the fcc Inconel-625 alloy used as a representative example. Dissipative processes occurring in this alloy are assessed through the complex interplay between the released heat, acoustic emission waves, and expended and stored elastic energy.

scholarly journals Use of Acoustic Emission for Testing Resistance of Hooves

2018 ◽  
Vol 66 (1) ◽  
pp. 29-33
Author(s):  
Petr Dostál ◽  
Zdeněk Havlíček ◽  
Lucie Kratochvílová
Keyword(s):  
Acoustic Emission ◽  
Mechanical Load ◽  
Testing Machine ◽  
Acoustic Emissions ◽  
Measured Data ◽  
Materials Testing ◽  
Emission Method ◽  
Experimental Part ◽  
Three Samples ◽  
Testing Resistance

This paper deals with the possibility of using an acoustic emission method for testing tensile strength of hooves. By using the acoustic emission (AE) method, we are able to locate degraded areas in hooves and then estimate the extent of degradation. In the experimental part, a sensor was used to record the emission signals, the measured data were processed and analysed, and the response of hooves to the applied mechanical load over time was monitored. Altogether, three samples were tested on the Zwick Z050/TH 3A materials testing machine and simultaneously the acoustic emissions were measured during testing.

scholarly journals Characterization of Historic Binders and Stones of a Ruined Medieval Church (Hungary)

2020 ◽  
Author(s):  
Zsuzsanna Kósa ◽  
Ákos Török
Keyword(s):  
Moisture Content ◽  
Construction Materials ◽  
Selective Dissolution ◽  
Test Methods ◽  
Schmidt Hammer ◽  
Fine Grained ◽  
Medieval Church ◽  
History Of ◽  
Non Destructive

Construction materials of a partly ruined Medieval church of Central Hungary were studied in details to assess its conditions and to obtain information on the phases of construction. At first, digital images were taken to create a 3D model of the remaining walls. The material properties were measured in situ using non-destructive test methods. Strength parameters of stone and render were assessed by Schmidt hammer, while moisture content was measured by a portable moisture meter. According to lithological descriptions and thin-section analyses limestone prevail in the monument. The most common Miocene limestone is represented by various lithologies, such as cemented macro porous limestone, fine-grained porous limestone, oolitic limestone and bioclastic limestone. Mesozoic micritic well cemented limestone and Tertiary limonitic sandstone were also identified at the ruins. The most common weathering forms are selective dissolution, multiple flaking and biological colonisation. Renders used in the structure represents the long history of the structure from Medieval lime-based mortars to Portland cement containing latest applications. The former one is composed of quartz send in lime binder. According to Schmidt hammer tests, the rebound values of the replacement stone is higher than that of the original porous limestone. There is a distinct difference in the moisture content of the stone and render. Orientation/exposure of the wall also influences the moisture content. The gathered information allows for designing better repair methods and helps in the planning of the maintenance of the medieval stone heritage.

Health Monitoring of Medieval Masonry Towers by an Acoustic Emission Approach

2019 ◽  
Vol 817 ◽  
pp. 586-593
Author(s):  
Giuseppe Lacidogna ◽  
Gianni Niccolini ◽  
Alberto Carpinteri
Keyword(s):  
Acoustic Emission ◽  
Health Monitoring ◽  
Masonry Wall ◽  
Masonry Buildings ◽  
Earthquake Occurrence ◽  
Structural Element ◽  
Natural Time ◽  
Non Destructive

Non-destructive tests were performed to assess cracking evolution in two medieval masonry buildings, Sineo and Asinelli towers rising respectively in the Cities of Alba and Bologna, in Italy. As regards the case study of Alba, in situ compressive flat-jack tests on small-sized elements of the tower were conducted in conjunction with acoustic emission (AE) monitoring. At the same time, crack patterns taking place in large volumes of the tower were likewise monitored through the AE technique.As for the case study of Bologna, a masonry wall of the Asinelli tower was monitored during a period of intense seismic activity. The observed correlation between the AE activity in the monitored structural element and local earthquakes points out a significant dependence of deterioration processes in the tower on the action of nearby earthquakes.In both cases, the trends of two evolutionary parameters, the b-value and the natural time (NT) variance κ1, were derived from the AE time series to identify the approach of the monitored structures to a critical state in relation to the earthquake occurrence.

Microstructure and stiffness of Scots pine (Pinus sylvestris L) sapwood degraded by Gloeophyllum trabeum and Trametes versicolor – Part I: Changes in chemical composition, density and equilibrium moisture content

Holzforschung ◽  
2012 ◽  
Vol 66 (2) ◽  
Author(s):  
Thomas K. Bader ◽  
Karin Hofstetter ◽  
Gry Alfredsen ◽  
Susanne Bollmus
Keyword(s):  
Moisture Content ◽  
Pinus Sylvestris ◽  
Mass Loss ◽  
Sample Size ◽  
Equilibrium Moisture Content ◽  
Scots Pine ◽  
Trametes Versicolor ◽  
Mass Density ◽  
Gloeophyllum Trabeum ◽  
Physical And Chemical

Abstract Fungal degradation alters the microstructure of wood and its physical and chemical properties are also changed. While these changes are well investigated as a function of mass loss, mass density loss and changes in equilibrium moisture content are not well elucidated. The physical and chemical alterations are crucial when linking microstructural characteristics with macroscopic mechanical properties. In the present article, a consistent set of physical, chemical and mechanical characteristics is presented, which were measured on the same sample before and after fungal degradation. In the first part of this two-part contribution, elucidating microstructure/stiffness-relationships of degraded wood, changes in physical and chemical data are presented, which were collected from specimens of Scots pine (Pinus sylvestris) sapwood degraded by Gloeophyllum trabeum (brown rot) and Trametes versicolor (white rot) for up to 28 weeks degradation time. A comparison of mass loss with corresponding mass density loss demonstrated that mass loss entails two effects: firstly, a decrease in sample size (more pronounced for G. trabeum), and secondly, a decrease of mass density within the sample (more pronounced for T. versicolor). These two concurrent effects are interrelated with sample size and shape. Hemicelluloses and cellulose are degraded by G. trabeum, while T. versicolor was additionally able to degrade lignin. In particular because of the breakdown of hemicelluloses and paracrystalline parts of cellulose, the equilibrium moisture content of degraded samples is lower than that in the initial state.

In Situ Analysis of Hygrothermal Performance of the Sedlec Ossuary

2015 ◽  
Vol 1126 ◽  
pp. 22-27
Author(s):  
Zbyšek Pavlík ◽  
Lukáš Balík ◽  
Jiří Maděra ◽  
Lucie Kudrnáčová ◽  
Robert Černý
Keyword(s):  
Czech Republic ◽  
Moisture Content ◽  
Moisture Distribution ◽  
Wall Surface ◽  
Moisture Meter ◽  
Hygrothermal Performance ◽  
Historical Masonry ◽  
Destructive Measurement ◽  
Non Destructive

In situ analysis of hygrothermal state of the Sedlec Ossuary, Czech Republic, is presented in the paper. Within the experimental analysis, the measurement of moisture distribution in several profiles of historical masonry is done on a gravimetric principle. Non-destructive measurement of moisture content on the wall surface is done as well, using a capacitive moisture meter. Moreover, the interior and exterior climate is monitored over an almost two year period. On the basis of the obtained experimental results the hygrothermal conditions in both the masonry and the interior are assessed, including the identification of main moisture sources.

Correlation of Acoustic Emission and Corrosion Resistance of Lacquer Coatings on Tin-Free Steel

2015 ◽  
Vol 659 ◽  
pp. 628-632
Author(s):  
Pornsak Srisungsitthisunti ◽  
Siriporn Daopiset ◽  
Noparat Kanjanaprayut
Keyword(s):  
Acoustic Emission ◽  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Corrosion Damage ◽  
Corrosion Monitoring ◽  
Metallic Structures ◽  
Crack Monitoring ◽  
Before And After ◽  
Non Destructive

Acoustic emission (AE) is a non-destructive technique which is well known for crack monitoring. Moreover, it has been widely used for corrosion and erosion damage on metallic structures. In this study, AE technique was applied for quick monitoring of corrosion resistance of lacquer coatings on tin free steel and laminated steel for food can-packaging. There were three types of coatings: (A) BPA-NI lacquer, (B) BPA-complied lacquer, and (C) PET lamination. These coatings were investigated in flat-sheet and in deformed sheet. Cathodic disbonding (CD) technique was carried out to cause separation between the coating and the metal substrate and initialize corrosion damage. AE signals was detected immediately with potential excitation, and showed good correlation with coating corrosion resistance during corrosion development. AE count signal matched with resulting current during CD, and proportional to corroded areas. In addition, coatings properties were measured before and after the CD process by electrochemical impedance spectroscopy (EIS). A combination of AE and CD techniques offers an in-situ non-destructive corrosion monitoring of coating quality before and during delamination development, and useful for can-packaging testing.

scholarly journals Methodology for the in situ testing of the moisture content of brick walls: an example of application

2020 ◽  
Vol 20 (4) ◽  
Author(s):  
Anna Hoła
Keyword(s):  
Moisture Content ◽  
Fourteenth Century ◽  
In Situ Testing ◽  
Negative Effects ◽  
Non Destructive ◽  
Historical Periods ◽  
Destructive Methods ◽  
Author Knowledge

Abstract The article presents original methodology of testing the moisture content of brick walls in buildings. It was developed on the basis of own experience acquired during testing the moisture content in many excessively wet buildings erected in various historical periods. The tests were conducted using different methods, including non-destructive methods. To emphasize the importance of the problem, an overview of the methodology was preceded by a brief presentation of the causes and negative effects of excessive moisture and salinity in brick walls. In addition, the article is illustrated with an example of the effects of moisture content tests carried out according to the developed methodology on a facility from the fourteenth century. According to the author, knowledge of the presented methodology, and its application, should contribute to both the improvement of the quality of conducted research and the credibility of the obtained results.

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