Ranking larch genotypes with the Rigidimeter: relationships between modulus of elasticity of standing trees and of sawn timber

Many biomechanical models include modulus of elasticity (E) but it is not always available in the literature. It would be useful to directly measure E for species, and one of the standard techniques for doing so is to utilize a universal testing machine (UTM). While laboratory testing can determine static flexural modulus of elasticity using a UTM, it requires destructive sampling and therefore is only useful after a tree or limb has been removed. Acoustic testing can be used to estimate the dynamic modulus of elasticity (DMOE) of wood, by measuring the speed of sound through a sample of wood without the need to remove any wood samples. This research investigated if acoustic testing can be used to accurately estimate the modulus of elasticity of green wood. Stump sprouts arising after a shelterwood harvest were cut and left at room temperature (21.1°C, warm) or conditioned to -6.7°C (frozen). The modulus of elasticity was measured using a stress-wave timer (DMOE) and a UTM (ES). The DMOE was higher in the frozen samples, but temperature did not affect ES. While the stress-wave timer used in the study found a slightly higher E than a UTM, a simple prediction equation was determined for converting the results. Researchers believe tools such as this can be successfully utilized by the arboriculture industry to rapidly assess the modulus of elasticity of standing trees in the field.

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Predicting the static modulus of elasticity in eastern cottonwood (Populus deltoides) using stress wave non-destructive testing in standing trees

European Journal of Wood and Wood Products ◽

10.1007/s00107-016-1043-0 ◽

2016 ◽

Vol 74 (6) ◽

pp. 885-892 ◽

Cited By ~ 1

Author(s):

Mehrab Madhoushi ◽

Soheyla Daneshvar

Keyword(s):

Stress Wave ◽

Modulus Of Elasticity ◽

Populus Deltoides ◽

Non Destructive Testing ◽

Destructive Testing ◽

Eastern Cottonwood ◽

Static Modulus ◽

Standing Trees ◽

Static Modulus Of Elasticity ◽

Non Destructive

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Applying Machine Strength Grading System to Round Timber Used in Hydraulic Engineering Works

Forests ◽

10.3390/f12030281 ◽

2021 ◽

Vol 12 (3) ◽

pp. 281

Author(s):

Michela Nocetti ◽

Giovanni Aminti ◽

C. Brand Wessels ◽

Michele Brunetti

Keyword(s):

Modulus Of Elasticity ◽

Dynamic Modulus ◽

Acoustic Velocity ◽

Hydraulic Engineering ◽

Raw Material ◽

Dynamic Modulus Of Elasticity ◽

Sawn Timber ◽

Mechanical Selection ◽

Round Timber ◽

Selection Of

Round timber is often used for hydraulic engineering works, but the strength grading of round logs is not as well developed as that of sawn timber. The advantages of using defined strength classes, as well as the proper selection of the raw material, could be applicable to hydraulic works as well. In this study, the methods and rules developed for sawn timber were applied to the mechanical selection of oak round logs, paying particular attention to the issue of the simplicity of grading operations and the moisture content of the timber. Both the acoustic velocity and dynamic modulus of elasticity of oak logs were measured with different instruments before performing destructive bending tests; machine settings were derived for both properties and dry and wet grading operations were simulated to compare efficiency. The use of the dynamic modulus of elasticity makes machine grading more efficient. On the other hand, the use of acoustic velocity alone is feasible and makes the procedure much faster, even if wet grading resulted in very conservative estimations. The yields obtained were similar for lower grades, but to achieve higher strength classes, the dynamic modulus was preferable. For very fast and less expensive measurements, velocity could be considered an appropriate method, as an improvement over the use of unselected material.

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Quality and Bending Properties of Scots Pine (Pinus Sylvestris L.) Sawn Timber

Forests ◽

10.3390/f11111200 ◽

2020 ◽

Vol 11 (11) ◽

pp. 1200

Author(s):

Izabela Burawska-Kupniewska ◽

Sławomir Krzosek ◽

Piotr Mańkowski ◽

Marek Grześkiewicz

Keyword(s):

Mechanical Properties ◽

Scots Pine ◽

Modulus Of Elasticity ◽

Bending Strength ◽

Mechanical Parameters ◽

Bending Properties ◽

Characteristic Values ◽

Sawn Timber ◽

The Moment

The paper presents the partial research results of a mechanical properties study conducted on Scots pine from the Silesian Forestry Area in Poland. The scope of research included the visual strength grading of the timber according to the PN-D-94021:2013 standard, mechanical testing (according to EN 408:2012) and an attempt to assign visuals to the C strength classes. The EN 1912: 2012 standard assigns the visual sorting classes of individual wood species (according to national sorting standards) to the C strength classes introduced by the EN 338: 2018 standard. At the moment, this standard does not assign Polish visual sorting classes (KW, KS, and KG) to C strength classes. The obtained MOE (modulus of elasticity) and MOR (static bending strength) values were corrected according to the EN 384:2018 standard, and their characteristic values were later calculated. On this basis, we proposed a classification of the grading classes determined on the basis of PN-D-94021 into C classes described in EN 338:2018, which is necessary in the process of the transposition of Polish strength grades (KW, KS, KG, and Reject) and the qualification of them in line with EN 1912:2012. The calculated characteristic values of density, MOR and E0 (the modulus of elasticity parallel to the grain) allowed us to assign Polish visual grades KW, KS, and KG to C35, C30, and C20, respectively. The pine timber under research had high physical and mechanical parameters, which translated into high C classes to which the KW, KS, and KG timber categories were assigned.

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Efficiency of Visual and Machine Strength Grading of Sawn Timber with Respect to Log Type

Forests ◽

10.3390/f12111467 ◽

2021 ◽

Vol 12 (11) ◽

pp. 1467

Author(s):

Izabela Burawska-Kupniewska ◽

Sławomir Krzosek ◽

Piotr Mańkowski

Keyword(s):

Modulus Of Elasticity ◽

Bending Strength ◽

Strength Class ◽

Limited Extent ◽

Visual Method ◽

Medium Quality ◽

Sawn Timber ◽

Machine Strength

A batch of pine timber sawn from butt, middle and top logs was strength graded with the visual method (classification into grading classes KW—best quality, KS—medium quality, KG—inferior quality and Reject) and with the machine strength grading method—performed with the use of a mobile timber grader (classification into C strength classes). We compared the efficiency of grading classes and strength classes, depending on the type of log from which the material was obtained (butt, middle, top). Next, a strength grading machine was used to measure the modulus of elasticity in bending (MOE) and static bending strength (MOR). The ANOVA confirmed the influence of both the log type (butt, middle, top), the C strength class, and the visual strength grading class on the values of density (DEN) and MOR. Timber density and MOR decreased from the butt log section to the top log section. The ANOVA confirmed the influence of log type on MOE values, but only to a limited extent.

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A new experimental device for rapid measurement of the trunk equivalent modulus of elasticity on standing trees

Annals of Forest Science ◽

10.1051/forest:2000126 ◽

2000 ◽

Vol 57 (4) ◽

pp. 361-359 ◽

Cited By ~ 8

Author(s):

Jean Launay ◽

Philippe Rozenberg ◽

Luc Paques ◽

Jean-Marc Dewitte

Keyword(s):

Modulus Of Elasticity ◽

Experimental Device ◽

Rapid Measurement ◽

Standing Trees ◽

Equivalent Modulus

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Modulus of elasticity as a criterion for strength grading of structural sawn timber

Annals of WULS, Forestry and Wood Technology ◽

10.5604/01.3001.0013.7723 ◽

2019 ◽

Vol 105 ◽

pp. 91-97

Author(s):

SŁAWOMIR KRZOSEK ◽

IZABELA BURAWSKA-KUPNIEWSKA ◽

PIOTR MAŃKOWSKI ◽

MAREK GRZEŚKIEWICZ ◽

ANDRZEJ MAZUREK

Keyword(s):

Modulus Of Elasticity ◽

Dynamic Modulus ◽

Elasticity Modulus ◽

Wood Technology ◽

Static Modulus ◽

Forest Regions ◽

Sawn Timber ◽

Static Modulus Of Elasticity ◽

Forest District ◽

Machine Strength

Modulus of elasticity as a criterion for strength grading of structural sawn timber. The paper presents an analysis that was performed on sawn timber originating from the Silesian Forest District in terms of parameters related to the elastic properties of the material. As part of the research, static modulus of elasticity (in accordance with EN 408: 2010 + A1: 2012) and dynamic modulus (using a portable device for machine strength grading) were determined. Both elasticity modulus were correlated with the density of the material, and compared with the database developed on the basis of previous research carried out at Faculty of Wood Technology of WULS- SGGW, including the results of strength grading of sawn timber from five natural Polish forest regions.

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MECHANICAL PROPERTIES OF POLISH-GROWN PINUS SYLVESTRIS L. STRUCTURAL SAWN TIMBER FROM THE BUTT, MIDDLE AND TOP LOGS

Wood Research ◽

10.37763/wr.1336-4561/66.2.231242 ◽

2021 ◽

Vol 66 (2) ◽

pp. 231-242

Author(s):

Sławomir Krzosek ◽

Marek Grześkiewicz ◽

Izabela Burawska Kupniewska ◽

Piotr Mańkowski ◽

Marek Wieruszewski

Keyword(s):

Mechanical Properties ◽

Pinus Sylvestris ◽

Modulus Of Elasticity ◽

Ring Width ◽

Modulus Of Rupture ◽

Bending Test ◽

Average Growth ◽

Growth Ring Width ◽

Annual Growth Rings ◽

Sawn Timber

The research consisted in testing Polish sawn timber dedicated for construction applications made of pines (Pinus sylvestris L.) that grew in the Silesian Forestry Region, taking into account three parts of the log: butt, middle and top. The boards had the same cross section, a nominal thickness of 40 mm and width of 138 mm, typical for Polish structural timber. The mean nominal length of the boards under research amounted to 3500 mm. Each set was composed of 70 boards. Before the tests, boards were dried in an industrial drier until reaching the moisture content of 12%, and they were planed on 4 sides. First of all, the sawn timber was graded into strength classes, and their dynamic modulus of elasticity (MOE_dyn) was tested with a non-destructive method, with the use of a portable MTG device. The next step consisted in a bending test with four points of support, according to the EN 408 standard, and with the use of the TiraTest 2300 machine, in order to determine the global modulus of elasticity (MOE_EN-408) and the static bending strength, also referred to as modulus of rupture (MOR). Finally, the average growth ring width was determined for each board (PN-D-94021), as well as wood density according to EN-408. The hereby paper presents the test results for all the tested sawn timber boards, taking into account the part of log that each board came from: butt, middle or top. The hereby paper presents the influence of density on the mechanical properties of wood, taking into account the location on the round timber. The analysis does not include the influence of the width of annual growth rings and the proportion of latewood on the wood properties under research.

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Estudio comparativo entre valores característicos experimentales y normativos de madera aserrada de pino silvestre = Comparative study between experimental and normative values of sawnwood of wild pine

Anales de Edificación ◽

10.20868/ade.2017.3570 ◽

2017 ◽

Vol 3 (2) ◽

pp. 39

Author(s):

Enrique Gómez de la Peña ◽

Alfonso Cobo Escamilla ◽

Rafael Lozano Díez ◽

Oscar López Zaldívar

Keyword(s):

Comparative Study ◽

Mechanical Behavior ◽

Modulus Of Elasticity ◽

Normative Values ◽

Different Types ◽

Sawn Timber

ResumenEste trabajo realiza un estudio comparativo de caracterización de vigas de madera aserradas y su comparación con la normativa. Para ello se ha utilizado dos tipos de madera muy diferentes, una muy heterogenea, con gran número de defectos, y otra muy homogénea, para comprobar la influencia de los nudos en el comportamiento mecánico de la madera. Para ello se han ensayado un total de 18 vigas de madera y 5 probetas a compresión. Posteriormente se ha realizado una comparativa con la normativa de caracterización, para comprobar su grado de definición. Se ha podido comprobar que dicha norma, se encuentra en el lado de la seguridad en el ámbito de las resistencias, pero que su definición es escasa en cuanto al módulo de elasticidad de la madera.AbstractThis work makes a comparative study of the characterization of sawn timber and its comparison with the standard. For this purpose, two very different types of wood have been used, one very heterogeneous, with a large number of defects, and a very homogeneous one, to verify the influence of the knots on the mechanical behavior of the wood. To this end, a total of 18 wooden beams and 5 test specimens have been tested. Subsequently a comparison has been made with the standardization of characterization, to verify its degree of definition. It has been possible to verify that this norm, is in the side of the security in the field of the resistances, but that its definition is scarce as far as the modulus of elasticity of the wood.

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