Models to estimate longitudinal compressive strength of Brazilian hardwood based on apparent density

Lahr, Francisco Antônio Rocco; Arroyo, Felipe Nascimento; Rodrigues, Edson Fernando Castanheira; Almeida, João Paulo Boff; Aquino, Vinícius Borges de Moura; Wolenski, Anderson Renato Vobornik; Santos, Herisson Ferreira dos; Ferraz, André Luiz Nonato; Chahud, Eduardo; Molina, Júlio César; Pinheiro, Roberto Vasconcelos; Christofóro, André Luis

doi:10.15376/biores.16.1.1373-1381

Cited by 9 publications

(10 citation statements)

References 11 publications

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“…It is worth noting that the average values of the properties (ρap,12% and fc0), as well as the resistance classes categorized here, are in accordance with those obtained previously PEER-REVIEWED ARTICLE bioresources.com by Jesus et al (2015), Dias et al (2019), Duarte et al (2020), andLahr et al (2021).…”

Section: Resultssupporting

confidence: 91%

Influence of specimen dimensions in the determination of strength and modulus of elasticity in static bending of hardwoods

Almeida

Rodrigues

Mascarenhas

et al. 2022

BioRes

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In Brazil, standard ABNT NBR 7190 (1997) prescribes the determination of strength (fM) and modulus of elasticity (EM) in static bending from specimens measuring 5 cm × 5 cm × 115 cm. Thus, the relationship between the test span (L) and the specimen height (h) greater than or equal to 21 (L/h ≥ 21) is respected, ensuring that the effect of shear in the calculation of displacements is negligible (Euler Bernoulli Theory). Considering the expressive number of tree species cataloged in the Brazilian Amazon Forest, any procedure that aims to facilitate the realization of experimental tests is highly desirable because it provides the knowledge of unusual species. These wood species may potentially replace woods that have been traditionally used and historically exploited. Using five hardwood species, this research aimed to verify, while maintaining constant L/h ≥ 21 ratios, the influence of specimens dimensions in the determination of fM and EM. For all species studied, the statistical analysis found equivalence in the values of fM and EM determined as a function of the sample sizes. Therefore, respecting the ratio L/h ≥ 21, the size of the specimens does not influence the determination of strength and stiffness in static bending.

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Section: Resultssupporting

confidence: 91%

Influence of specimen dimensions in the determination of strength and modulus of elasticity in static bending of hardwoods

Almeida

Rodrigues

Mascarenhas

et al. 2022

BioRes

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“…However, performing this type of test also requires the use of unique equipment that is often costly. In this context, several studies have shown that it is possible to estimate a property that is difficult to obtain through another that is more easily obtained by means of regression models with significant adjustments (Almeida et al 2014;Wolenski et al 2020;Lahr et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Estimation of toughness as a function of compression strength parallel to the grain of tropical woods

Ruthes

Santos²,

Araújo

et al. 2023

BioRes

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Tropical species are widely used in construction, and their physical and mechanical properties have been important characteristics with direct impact on the design of structures, especially the strength and stiffness of wood applied in them. Tests to obtain both parameters are conducted under ABNT NBR 7190 (1997) guidelines in Brazil, being rarely found in some research centers because of the higher costs of testing equipment. For instance, the toughness test depends on equipment with a pendulum, whose device requires accuracy and maintenance for reliable analyses. This paper aims to estimate toughness through another property more easily found, given by the compression strength parallel to the grain. For this, 20 tropical wood species of the South American region were used to obtain initial values of these properties. The characteristic values of the compression strength parallel to the grain as well as linear and quadratic regression models were obtained. Statistical analysis was performed and confirmed that a linear model gave better predictions than a quadratic model.

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“…However, the vast majority of these tests require the use of specific equipment that is only found in large research centers. This fact makes characterizations of this nature difficult, given the scarcity of laboratories of this magnitude in Brazil [7]. Due to this scarcity, the standards establish numerical correlations that allow the determination of mechanical properties through mathematical models, e.g., Equations ( 1)-(3) of NBR 7190 [6], where f c0,k is the characteristic fiber parallel compressive strength, f t0,k the characteristic fiber parallel tensile strength, and f m,k the characteristic flexural tensile strength.…”

Section: Introductionmentioning

confidence: 99%

Estimation of Flexural Tensile Strength as a Function of Shear of Timber Structures

Arroyo,

Borges,

Junior

et al. 2023

Forests

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To avoid the intrinsic difficulties regarding the characterization of wood (i.e., different applications in different directions), various normative documents present the relationships between properties; the Brazilian standard is of particular interest in this regard, because Brazil has a huge diversity of tree species from tropical forests, usually used in construction. In view of this, this research aimed to propose a new list of properties to be inserted in future versions of the Brazilian standards in order to help identify the species shear strength. It is expected that there is a correlation between the characteristic values of flexural strength (fm,k) and shear strength in the direction parallel to the wood fibers (fv,0,k), leading to models that make it possible to estimate one of the properties if the other is known, which was the main objective of this research. After finding a strong correlation between the properties, various regression models were evaluated. It can be concluded that the linear model composed only by the angular coefficient (equation with only one variable) presented a determination coefficient of 76.45%, which shows the good precision achieved in the estimation of one of the two variables compared if the other is known. Additionally, an attempt was made to define which probability distribution represents the resistance data by applying maximum likelihood (MLE), concluding that there is little difference between the representation by the normal distribution and the generalized extreme value (GEV) distribution. Another approach was to define the undermining coefficient to ensure the reliability of the prediction equation by the experiment-based calibration methodology defined by Eurocode.

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Models to estimate longitudinal compressive strength of Brazilian hardwood based on apparent density

Cited by 9 publications

References 11 publications

Influence of specimen dimensions in the determination of strength and modulus of elasticity in static bending of hardwoods

Influence of specimen dimensions in the determination of strength and modulus of elasticity in static bending of hardwoods

Estimation of toughness as a function of compression strength parallel to the grain of tropical woods

Estimation of Flexural Tensile Strength as a Function of Shear of Timber Structures

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