Active Thermography in Diagnostics of Timber Elements Covered with Polychrome

Kucharska, Milena; Jaskowska-Lemańska, Justyna

doi:10.3390/ma14051134

Cited by 11 publications

(7 citation statements)

References 42 publications

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“…In the case of historic structures, one can often encounter additional limitations, such as the presence of polychrome, which, on the one hand, can affect the results of the study and, on the other hand, significantly hinder the implementation of research work. One potential solution is the application of the active thermal imaging method [36]. In connection with this, as a further direction of research, we can indicate the analysis of the influence of finishing the element with paint layers as well as various types of surface treatment (e.g., drying and impregnation) on the research results.…”

Section: Discussionmentioning

confidence: 96%

Correction Factors for Sclerometric Test Results in the Technical Assessment of Timber Structural Elements under Diverse Conditions

Jaskowska-Lemańska,

Wałach,

Górka-Stańczyk

2023

Materials

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Research on existing wooden structures relies on non-destructive and semi-destructive techniques. One of the methods enabling the estimation of the physico-mechanical characteristics of wood in building structures based on established correlational relationships is the sclerometric method. The challenge in utilizing these known correlational relationships is the lack of data regarding the impact of frequently occurring factors in objects on sclerometric test results. This paper presents the influence of selected factors on the results of sclerometric tests, such as temperature, the direction of testing in relation to annual growth rings, and the physical orientation of the measuring device. The research was conducted on pine, spruce, and fir elements, each subjected exclusively to the influence of one of these factors. The study indicates that these factors should not be overlooked in assessing technical conditions using sclerometric testing methods. The impact of temperature on sclerometric test results is relatively small; a change in temperature of 10 °C results in an average test outcome change of approximately 3%. Conversely, changing the orientation of the measuring device from horizontal to vertical can alter the test result by up to 10%. The direction of testing relative to the annual increments of wood also has a significant impact on the test results, but incorporating this factor into practice seems to be quite difficult, and in the case of elements with substantial cross-sections, it is also not required. The obtained results enable the application of established correlational relationships in the structural analysis of wooden elements for which access is challenging, especially under temperature conditions different from the reference, 20 °C.

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Section: Discussionmentioning

confidence: 96%

Correction Factors for Sclerometric Test Results in the Technical Assessment of Timber Structural Elements under Diverse Conditions

Jaskowska-Lemańska,

Wałach,

Górka-Stańczyk

2023

Materials

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“…The knot area ratio is assessed in the cross-section with the highest concentration of defects, regardless of the distance of this concentration from the end of the element. Further details of the method of assessing the quality class and the KAR index are presented in the works of [ 21 , 22 ], among others. The assignment of a given piece of timber to a certain quality class was made based on the standard PN-D-9402:2013 [ 23 ]—which is based on European guidelines contained in the standard EN 14081-1:2007 [ 24 ].…”

Section: Methodsmentioning

confidence: 99%

Assessment of the Technical Condition of Timber Structural Elements Using Sclerometric Tests

Jaskowska-Lemańska,

Wałach

2023

Materials

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The technical assessment of wooden elements is the primary step in their repair and reinforcement design. Normative requirements currently mandate additional tests, including semi-destructive ones, beyond traditional visual assessment. Despite the growing feasibility of semi-destructive tests for qualitative assessments, there remains a paucity of data enabling quantitative assessments. This study investigated the hardness of structural timber, specifically pine, spruce, and fir, from Central Europe using sclerometric methods. The outcomes of these tests were compared with those of conventional destructive tests and correlational relationships were established. A strong correlation was found between the sclerometric tests and density (r = 0.62 ÷ 0.82), while a range of strong to moderate correlations was found (r = 0.40 ÷ 0.70) for mechanical characteristics (bending and compressive strength). The correlation strength varied among different wood species, with the strongest for pine and the weakest for spruce. All established relationships were compiled into 40 functions to facilitate their future utilization in quantitative assessments during the technical evaluation of wooden objects. The study also examined the influence of wood defects on the derived correlations by considering the knot index. Sclerometric methods accurately reflect the physico-mechanical properties of elements with a small or medium defect content. However, for wood with a high proportion of defects (knots), the correlations are very weak (r = 0.23 ÷ 0.52, including statistically insignificant results). This research offers new insights into the potential of semi-destructive methods in the structural evaluation of wooden elements, highlighting the need to account for wood species and defect content.

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“…Results indicated the method's ability to estimate knot positions due to temperature variations, with the air heater being the most effective source. However, limitations include the need for access to all sides of the wood element and the subjective measurement of knot diameter in thermal images [46]. Gallego et al used the IRT technique to inspect the width, length, and depth of superficial cracks in wooden beams.…”

Section: Non-destructive Testingmentioning

confidence: 99%

Imaging of Structural Timber Based on In Situ Radar and Ultrasonic Wave Measurements: A Review of the State-of-the-Art

Pahnabi,

Schumacher,

Sinha

2024

Sensors

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With the rapidly growing interest in using structural timber, a need exists to inspect and assess these structures using non-destructive testing (NDT). This review article summarizes NDT methods for wood inspection. After an overview of the most important NDT methods currently used, a detailed review of Ground Penetrating Radar (GPR) and Ultrasonic Testing (UST) is presented. These two techniques can be applied in situ and produce useful visual representations for quantitative assessments and damage detection. With its commercial availability and portability, GPR can help rapidly identify critical features such as moisture, voids, and metal connectors in wood structures. UST, which effectively detects deep cracks, delaminations, and variations in ultrasonic wave velocity related to moisture content, complements GPR’s capabilities. The non-destructive nature of both techniques preserves the structural integrity of timber, enabling thorough assessments without compromising integrity and durability. Techniques such as the Synthetic Aperture Focusing Technique (SAFT) and Total Focusing Method (TFM) allow for reconstructing images that an inspector can readily interpret for quantitative assessment. The development of new sensors, instruments, and analysis techniques has continued to improve the application of GPR and UST on wood. However, due to the hon-homogeneous anisotropic properties of this complex material, challenges remain to quantify defects and characterize inclusions reliably and accurately. By integrating advanced imaging algorithms that consider the material’s complex properties, combining measurements with simulations, and employing machine learning techniques, the implementation and application of GPR and UST imaging and damage detection for wood structures can be further advanced.

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Active Thermography in Diagnostics of Timber Elements Covered with Polychrome

Cited by 11 publications

References 42 publications

Correction Factors for Sclerometric Test Results in the Technical Assessment of Timber Structural Elements under Diverse Conditions

Correction Factors for Sclerometric Test Results in the Technical Assessment of Timber Structural Elements under Diverse Conditions

Assessment of the Technical Condition of Timber Structural Elements Using Sclerometric Tests

Imaging of Structural Timber Based on In Situ Radar and Ultrasonic Wave Measurements: A Review of the State-of-the-Art

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