Prediction of bending properties for beech lumber using stress wave method

Güntekin, Ergün; Ozkan, S.; Yılmaz, Tuğba

doi:10.4067/s0718-221x2014005000008

Cited by 10 publications

(8 citation statements)

References 10 publications

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“…In this sense, efforts have been made around the globe in order to improve and better understand the technique potential and range. Guntekin et al [18] obtained a good correlation between the dynamic modulus of elasticity from the UPV test and the mechanical properties from bending tests in Turkey. Van de Kuilen and Ravenshorst [19], in the Netherlands, established relationships for the classification of tropical hardwoods from the combination of dynamic modulus of elasticity and density, based on the principle that woods of the same species can be classified in different classes.…”

Section: Introductionmentioning

confidence: 96%

Mechanical Characterization of Iroko Wood Using Small Specimens

et al. 2021

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Despite their favorable physical and mechanical properties for structural use, tropical woods, such as Iroko (Milicia excelsa), present knowledge gaps to be filled mainly about their mechanical characterization, which currently limit their use or result in under- or overdimensioned structural elements. Visual classification, one of the most used methods for characterizing wood, is inaccurate in the case of Iroko due to the wide variety of geographical locations in which this species can be found. In addition, mechanical characterization using test pieces with structural dimensions leads to high and impractical costs. In this context, this study aims to verify the mechanical properties of Iroko (imported from the Republic of the Congo) from small size specimens, a process that is currently standardized only for softwoods, and to verify the correlation of different properties through bending properties and ultrasound tests. Prior to the bending tests, the speed of propagation of ultrasonic waves was measured using the direct method. The results obtained show a good correlation between density and bending properties and the velocity of propagation of ultrasonic waves.

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Section: Introductionmentioning

confidence: 96%

Mechanical Characterization of Iroko Wood Using Small Specimens

et al. 2021

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“…Wood may be used for structural purposes (FREITAS;GONÇALEZ;DEL MANEZZI, 2016;TRIANOSKI et al, 2014) and the physical and mechanical characterization activities are important within this background (DAHLEN et al, 2017;PEREIRA et al, 2018;GUNTEKIN;OZKAN;YILMAZ, 2014). NBR 7190 (ABNT, 1997) "Design of Timber Structures" is the normative Brazilian code which prescribes both structural calculation and properties determination procedures.…”

Section: Introductionmentioning

confidence: 99%

Analytical study of the curve of static bending test for wood specimens

Almeida

Moritani

et al. 2020

Ambient. constr.

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The NBR 7190:1997 "Design of Timber Structures" provides the procedure for several mechanical tests, and among them, the Static bending test for Modulus of Elasticity (Em) and Conventional Value of Strength (fm) determinations. It is common to characterize wood batches with a small number of specimens, what makes it difficult to perform an estimative test for rupture determination, and afterwards, to carry out the loading cycle for Em estimation. In these cases, instead of Force parameters, Deflection parameters are used for the loading cycle. This paper aims to identify a pattern between Force and Deflection parameters by investigating the Force vs. Deflection curve of the static bending test of wood specimens. According to results, there is a well pronounced pattern between Force and Deflection parameters in the linear part of the Force vs. Deflection curve, and based on this, we proposed a linear regression model between logarithm values of the force percentage (in relation to the rupture) and the denominator of the span value (as a Deflection parameter), resulting R2 equal to 97.41%. This result makes the conduction of the static bending test easier in specialized laboratories for testing of wood.

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“…It is a material property that may be classified as either a positive or negative characteristic, depending on the purpose. In the Forests 2019, 10, 2 of 11 case of materials that are intended for bending, this property is desirable [6][7][8], whereas it is undesirable in materials that are intended for construction [9,10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Selected Factors on the Bending Deflection at the Limit of Proportionality and at the Modulus of Rupture in Laminated Veneer Lumber

Síkora¹,

Svoboda²,

Záborský³

et al. 2019

Forests

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The deflection of a test material occurs under bending stress that is caused by force. In terms of plasticity and elasticity, the deflection can be quantified at two main areas, which are the limit of proportionality and the modulus of rupture. Both of these deflections are of great importance in terms of the scientific and practical use. These characteristics are particularly important when designing structural elements that are exposed to bending stress in terms of the size of the deflection in their practical application. This study analyzed the effect on the size of the deflection at the limit of proportionality and at the modulus of rupture. Wood species (Fagus sylvatica L. and Populus tremula L.), material thickness (6 mm, 10 mm, and 18 mm), non-wood component (glass and carbon fiber), position of the non-wood component in the layered material (up and down side with respect to the loading direction), and adhesive used to join the individual layers (polyurethane and polyvinyl acetate) were the observed factors. Glass fiber reinforcement proved to be a better option; however, the effect of correctly selected glue for individual wood species was also apparent. For the aspen laminated materials, polyurethane adhesive (PUR) adhesive was shown to be a more effective adhesive and PVAc adhesive was better for the beech-laminated materials. These results are of great importance for the production of new wood-based materials and materials were based on non-wood components, with specific properties for their intended use.

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Prediction of bending properties for beech lumber using stress wave method

Cited by 10 publications

References 10 publications

Mechanical Characterization of Iroko Wood Using Small Specimens

Mechanical Characterization of Iroko Wood Using Small Specimens

Analytical study of the curve of static bending test for wood specimens

Effect of Selected Factors on the Bending Deflection at the Limit of Proportionality and at the Modulus of Rupture in Laminated Veneer Lumber

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