Estimation of Wood Toughness in Brazilian Tropical Tree Species

Christofóro, André Luis; Almeida, Diego Henrique de; Varanda, Luciano Donizeti; Panzera, Túlio Hallak; Lahr, Francisco Antônio Rocco

doi:10.1590/1809-4430-eng.agric.v40n2p232-237/2020

Cited by 9 publications

(5 citation statements)

References 14 publications

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“…A result similar to that for P. rigida heattreated at 150 ºC was reported by CHRISTOFORO et al (2020), who obtained a MOR value of 120.3 MPa when studying the wood of Piptadenia macrocarpa and E. grandis × E. urophylla exposed to 120 °C, 150 °C, and 180 ºC for 2 h; similar results were found in the literature as well when NOGUEIRA et al ( 2020) evaluated the wood of E. tereticornis and found a value of 131.0 MPa for the same property.…”

Section: Source Of Variation Dfsupporting

confidence: 87%

Thermal modification influences the mechanical resistance of wood from forestry species

et al. 2023

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This study evaluated the effects of thermal modification at different temperatures and for different durations on the mechanical strength of wood of selected species from an agroforestry system. To this end, three 9-year-old (approximate age) individuals, each from four species of forest trees-Parapiptadenia rigida (Benth.) Brenan, Peltophorum dubium (Spreng.) Taub., Eucalyptus grandis × Eucalyptus urophylla hybrid, and Schizolobium parahyba (Vell.) Blake-were evaluated. After obtaining initial measurements, samples from the four species under went heat treatment for 2 h and 4 h and were subsequently subjected to heat using an oven at temperatures 120°C, 150°C, 180°C, and 210°C; respectively, in addition to the control. For evaluating mechanical strength, the technical standard ASTM D 143-94 was used to obtain the values of the moduli of elasticity and rupture, tension at the proportional limit, and maximum force of the subjects. It was observed that different durations and temperatures altered the mechanical strength of the wood of the four species studied. The 2 h residence time is the most recommended for conducting thermal modification. This procedure modifies the mechanical resistance of wood in a positive manner, with exposure temperatures ranging between 120 ºC and 180 ºC being the most recommended. The thermal treatment carried out for 4 h is not recommended for structural purposes because of the decrease in flexural strength.

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Section: Source Of Variation Dfsupporting

confidence: 87%

Thermal modification influences the mechanical resistance of wood from forestry species

et al. 2023

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“…At this point, it is worth noting that the density was also significantly affected by the moisture content, in which the 12% increase in the fiber saturation point resulted in a 10.53% increase in this property. Christoforo et al (2020) showed, through the study of regression models involving species with varied densities, a good correlation between apparent density and calculated toughness at 12% moisture. The authors found that increases in density values impacted increases in toughness values.…”

Section: Resultsmentioning

confidence: 97%

Influence of moisture content on physical and mechanical properties of Cedrelinga catenaeformis wood

Soares

Fraga

Paula

et al. 2021

BioRes

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This study aimed to investigate the influence of moisture content variation on 12 mechanical properties of the Cedrelinga catenaeformis species. Of the 12 properties, four were significantly affected (based on analysis of variance at 5% significance level), and the compression and shear strengths in the direction parallel to the fibers exhibited the greatest difference in values from the saturated moisture condition of up to 12% (approximately 34% increase). Toughness exhibited a behavior different from that predicted by the normative equation, in which increase in moisture content implied increase (approximately 59%) of the property studied. Because a good part of the properties was not significantly affected and Brazilian standard ABNT NBR 7190 (1997) considers expressions that lead to a considerable increase in mechanical properties with the reduction of moisture content, this approach was unfavorable to the safety of the project, motivating the development of other studies to collaborate in revisions of this normative document.

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“…For the toughness property, such property was changed significantly by moisture content, with a reduction of 32% from 12% moisture value to FSP value, countering the behavior observed in other properties. In literature, the relationship between toughness and apparent density at 12% moisture shows an increase in W with apparent density enhancement (Christoforo et al, 2020b).…”

Section: Discussionmentioning

confidence: 99%

Evaluation of moisture content variation on strength and stiffness properties of Cedrella sp. wood specie

et al. 2022

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In order to evaluate the influence of moisture content on wood physical and mechanical properties, the present research analyzed the influence of moisture content variation on Cedrella sp. on 12 strength and stiffness properties, considering 12% moisture content up to Fiber Saturation Point (FSP) were considered. Brazilian Standard consider a correction on wood properties obtained on moisture content different of 12%, reducing the properties. Eight properties from these twelve were significantly influenced by moisture content according to statistical analysis (5% significance level). ANOVA, Anderson Darling and Multiple Comparison tests were used at 5% significance level. Considering that most of properties were affected by moisture content, the equations to estimate wood properties according to moisture decrease are quite precise, but most of estimations were higher than the experimental values at 12% moisture content, indicating the need of a standard review for such estimators, which may lead to an unsafe timber structure design. For a conclusive consideration of moisture content variation influence on wood products, further researches with other tropical wood species are required.

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Estimation of Wood Toughness in Brazilian Tropical Tree Species

Cited by 9 publications

References 14 publications

Thermal modification influences the mechanical resistance of wood from forestry species

Thermal modification influences the mechanical resistance of wood from forestry species

Influence of moisture content on physical and mechanical properties of Cedrelinga catenaeformis wood

Evaluation of moisture content variation on strength and stiffness properties of Cedrella sp. wood specie

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