Rheological model for wood

Hassani, Mohammad Masoud; Wittel, Falk K.; Hering, Stefan; Herrmann, Hans J.

doi:10.1016/j.cma.2014.10.031

Cited by 66 publications

(62 citation statements)

References 40 publications

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“…Additionally, Fu et al (2013) show that mechano-sorption is dependent on the radial position of the log. Hassani et al (2015) indicate that MS strain is greater in the perpendicular direction than in the parallel direction.…”

Section: Introductionmentioning

confidence: 99%

Hygromechanical strains during the drying of Eucalyptus nitens boards

Pérez-Peña

Cloutier

Segovia

et al. 2016

Maderas, Cienc. tecnol.

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Collapse and drying stresses are currently induced during the drying of Eucalyptus nitens in solid wood products. The purpose of this study was to investigate these drying stresses by measuring hygromechanical strains during the drying of Eucalyptus nitens boards.Small samples of Eucalyptus nitens wood were oriented in the radial and tangential directions and tested to determine the hygromechanical strains during the drying process. This experimental work consisted of cantilevered bending tests conducted under variable relative humidity conditions. Tests were performed in a conditioning chamber at 30 °C with an equilibrium moisture content ranging from 22 to 12% under four levels of stress: 0, 10, 20 and 30% of the rupture load. The strains were determined using strain gauges, and the total deflection was measured with a linear variable differential transformer.The results show that in hygromechanical strains during the drying of Eucalyptus nitens, both the surface deformation and mechano-sorption strain were found to be proportional to the applied stress and reached their maximum values in the tangential direction. The total deflection increased 0,18 mm/mm with a surface deformation of 0,20 mm/mm, and the mechano-sorptive strain provides a greater contribution with a value of 0,11 mm/mm, thus corresponding to 59% of the total deformation. In attempts to improve the drying schedules of Eucalyptus nitens to develop solid wood products, mechano-sorptive behavior may be applied to relieve collapse and drying stress.

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Section: Introductionmentioning

confidence: 99%

Hygromechanical strains during the drying of Eucalyptus nitens boards

Pérez-Peña

Cloutier

Segovia

et al. 2016

Maderas, Cienc. tecnol.

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“…Additionally, he shows that the off-diagonal components scale disproportionally to the diagonal components of all creep compliance matrices introduced in an orthotropic model. These findings are quite revolutionary and not easy to establish since they are violated in several creep models, for example, in Fortino et al (2009), andHassani et al (2015). The coupled formulation of creep by Frandsen (2007) accounts for the necessary requirements about the compliance matrix.…”

Section: Introductionmentioning

confidence: 99%

Coupled two-dimensional modeling of viscoelastic creep of wood

Huč

Svensson

2017

Wood Sci Technol

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Three coupled two-dimensional viscoelastic creep models for orthotropic material are analyzed. The models of different complexity are mathematically formulated and implemented in a finite element software. Required viscoelastic material parameters are determined by calibration procedure, where numerical results are compared against experimentally obtained viscoelastic strains caused by tensile or shear loading. Finally, a comparison method is used to evaluate the accuracy of strain predictions of each particular model. The analysis shows that all the models are able to accurately predict viscoelastic creep simultaneously in two perpendicular directions for various periods of time and wood species. Calculated numerical values of the viscoelastic material parameters suitable for the three models and wood species, i.e., Douglas fir (Pseudotsuga menziesii), Norway spruce (Picea abies), Japanese cypress (Chamaecyparis obtusa), and European beech (Fagus sylvatica L.), under constant tensile loading are also given.

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“…Some authors have proposed one-dimensional models to determine the deformation caused by the heat and mass transport, specifically, the shrinkage and mechano-sorptive strain (Chen et al 1997;Svensson and Martensson 2002;Kang et al 2004;Pang 2007). Additionally, twodimensional models have been proposed by authors such as Martensson and Svensson (1997), Perré and Turner (2001a,b), Cheng et al (2007), and Salinas et al (2011a); three dimensional models have been proposed by Ormarsson et al (1999 and2003), Remond et al (2006), and Hassani et al (2015).…”

Section: Introductionmentioning

confidence: 99%

Simulation of Drying Stresses in Eucalyptus nitens Wood

Pérez-Peña¹,

Chávez²,

Salinas³

et al. 2018

BioResources

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The objective of this work was to simulate the stresses produced during the drying of Eucalyptus nitens wood due to variations in the moisture content. The methodology involved experimental determination and simulation of drying stresses caused by the development of internal moisture content gradients. Modeling of the moisture transport was based on the concept of an effective diffusion coefficient. The mathematical model for stress-strain, and for moisture diffusion into the wood, was constituted by a system of second-order nonlinear partial differential equations with variable coefficients, which were numerically integrated by the control volume based on the finite element method (CVFEM). For validation purposes, tests were realized for evaluating deformations, stress drying, and moisture gradients that were produced during the drying of Eucalyptus nitens. The results showed satisfactory agreement between the experimental and simulated values, indicating an effective simulation.

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Rheological model for wood

Cited by 66 publications

References 40 publications

Hygromechanical strains during the drying of Eucalyptus nitens boards

Hygromechanical strains during the drying of Eucalyptus nitens boards

Coupled two-dimensional modeling of viscoelastic creep of wood

Simulation of Drying Stresses in Eucalyptus nitens Wood

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