A generalized mat consolidation model for wood composites

Zhou, Cheng; Dai, Chunping; Smith, Gregory D.

doi:10.1515/hf.2008.053

Cited by 12 publications

(7 citation statements)

References 17 publications

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“…The mat porosity had a substantial effect on thermal conductivity. This tendency was also reported by Dai et al [31], Thoemen et al [26], Sonderegger and Niemz [34] and Suleiman et al [14] in investigations on wood-based composite materials. The drastic decrease of thermal conductivity below 65% of mat porosity was evident.…”

Section: Discussionsupporting

confidence: 79%

“…A notable change from a random orientation towards a better orientation of fibers also seems to occur from 598 kg m −3 to 987 kg m −3 . Pettersson et al [25], Zhou et al [26], Dogu et al [22] have suggested a similar behavior when the oriented strand board (OSB) mat is compressed, and the strands begin to align themselves in the same direction. The images at 810 kg m −3 and 987 kg m −3 (Figure 7d,e) exhibited a more homogeneous and oriented structure in comparison to lower densities.…”

Section: Thermal Conductivity In Relation To Mat Porositymentioning

confidence: 97%

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Effect of Density and Fiber Size on Porosity and Thermal Conductivity of Fiberboard Mats

Rebolledo

Cloutier

Yemele

2018

Fibers

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The thermal conductivity and porosity of fiberboard mats are crucial parameters for efficient energy consumption of the hot-pressing process and for final panel quality. In this work, the effect of fiber size and mat density on porosity and thermal conductivity of the mat were investigated. The fiber size was characterized as fine, medium and coarse. The mat porosity was measured by image analysis using the black and white contrast method. The thermal conductivity was determined at different density levels with a temperature gradient of 1.6 °C mm−1 and 7.6% (s = 0.3) moisture content. The results showed that fiber size was a dominant variable governing heat conduction and mat porosity. The mats made with medium size fibers showed a higher resistance to compression. The thermal conductivity of coarse fiber mats decreased drastically between 700 kg m−3 and 810 kg m−3. This was likely due to a higher fracture frequency observed for coarse fibers in comparison to the other fiber sizes studied. Hence, the fine and medium fibers conducted heat more efficiently. Moreover, fiber bundles and fractured fibers were observed during the mat porosity measurements, principally in mats made with fine fiber size.

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Section: Discussionsupporting

confidence: 79%

Section: Thermal Conductivity In Relation To Mat Porositymentioning

confidence: 97%

Effect of Density and Fiber Size on Porosity and Thermal Conductivity of Fiberboard Mats

Rebolledo

Cloutier

Yemele

2018

Fibers

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“…Author details 1 Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki 305-8687, Japan. 2 Faculty of Agriculture, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan. 3 Shizuoka Professional University of Agriculture, Tomigaoka 678-1, Iwata-city, Shizuoka-ken 438-8577, Japan.…”

Section: Authors' Contributionsmentioning

confidence: 99%

“…Wood-based panels are generally manufactured by consolidating mats of resinated wooden raw materials (for example; strands, particles, or fibers) under a hot-pressing process [1][2][3]. Hot-pressing is a critical process that not only determines the physical and mechanical properties of wood-based panels [4][5][6][7], but also affects the energy consumption and costs on the production line [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Effect of face-layer moisture content and face–core–face ratio of mats on the temperature and vapor pressure behavior during hot-pressing of wood-based panel manufacturing

et al. 2021

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Wood-based panels are made by consolidating mats of resinous wooden raw materials under a hot-pressing process. This study investigates the effect of face-layer moisture content (MC) and face–core–face (FCF) ratio of mats on the temperature and vapor pressure behavior during the hot-pressing process. Raising the face-layer MC and lowering the face-layer thickness was expected to reduce the time of reaching 100 °C in the hot-pressing process. When the temperature rise was limited or the core temperature decreased after reaching 100 °C (defined as plateau in this study), the mats with 25% and 30% face-layer MC with 1:2:1 FCF ratio reached the highest plateau core temperature, but required a longer time to complete the plateau. The relationship between core plateau temperature and maximum core vapor pressure was well described by the Antoine equation, which empirically models the vapor pressure as a function of temperature. The Antoine equation held across both face-layer MC series (varying face-layer MC at constant FCF ratio) and FCF series (varying FCF ratio at constant face-layer MC). The mat with 20% face-layer MC and 1:2:1 FCF ratio reached 180 °C within the shortest time, regardless of the evaluation conditions.

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“…ness (Dai and Steiner 1997;Zombori et al 2001;Painter et al 2006). • Combination of these advances with prior deformation models of cellular solids (Gibson and Ashby 1988) and wood (Wolcott 1990) has led to the derivation of constitutive laws for mat consolidation based on the mechanisms of transverse wood compression (Dai and Steiner 1993;Dai 2001) and fiber bending (Lang and Wolcott 1996;Zhou et al 2008). • The mat structure model allows the analytical definition of mat porosity and permeability, which in turn leads to the prediction of the internal mat gas pressure during pressing (Dai and Yu 2004;Dai et al 2005Dai et al , 2007a.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional modeling of the structure formation and consolidation of wood composites

Drolet¹,

Dai

2010

Holzforschung

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A new three-dimensional (3D) computer simulation model is proposed to study structure development in wood composites, particularly strand or short fiber wood composites. The model takes into account the stochastic positioning and orientation of the strands within the mat. It also predicts the response of individual strands within the structure to the compressive and shear forces produced during mat consolidation. The model provides a complete description of mat structure in three dimensions, including spatial distribution of porosity, inter-strand contact, and density. Predictions for porosity obtained with the 3D model compare very well with those from an earlier two-dimensional analytical model. Mat structure is dictated by mat density in a two-step process: rapid removal of macrovoids before the mat density reaches the original wood density and asymptotic elimination of microvoids at higher mat densification. Other factors of importance include original wood density and strand dimensions, particularly strand thickness and width. Although known for its influence on mechanical properties, strand orientation seems to have little effect on mat porosity and strand contact.

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A generalized mat consolidation model for wood composites

Cited by 12 publications

References 17 publications

Effect of Density and Fiber Size on Porosity and Thermal Conductivity of Fiberboard Mats

Effect of Density and Fiber Size on Porosity and Thermal Conductivity of Fiberboard Mats

Effect of face-layer moisture content and face–core–face ratio of mats on the temperature and vapor pressure behavior during hot-pressing of wood-based panel manufacturing

Three-dimensional modeling of the structure formation and consolidation of wood composites

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