High temperatures in parallel or perpendicular wood grain direction: a numerical and experimental study

Fonseca, E.M.M.; Barreira, Luísa

doi:10.2495/safe110161

Cited by 4 publications

(4 citation statements)

References 7 publications

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“…Corresponding values at room temperature for wet (12% MC) and oven-dry (0% MC) DF and SP were adopted from the wood hand book [1] in Table 3. The conductivity in the parallel-tograin direction is higher than that in transverse direction [24][25][26][27]. According to the Forest Products Laboratory, the thermal conductivity along the grain is greater than conductivity across the grain by a factor of 1.5 to 2.8, with an average of about 1.8 [1].…”

Section: Thermal Conductivitymentioning

confidence: 99%

“…In this study, the conductivity values of wood and char in parallel-to-grain direction were assumed 1.5 times that in the transverse direction. This value was also adopted by Fonseca and Barreira [27] to predict the char-layer evolution of pine wood by taking into account the grain orientations. The conductivity after dehydration was assumed to be equal to that of the virgin wood since the thermal conductivity increases only slightly from ambient temperature up to the end of dehydration in models such as Mehaffey and EC5.…”

Section: Thermal Conductivitymentioning

confidence: 99%

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Experimental and Three-Dimensional Numerical Investigations of Dehydration and Pyrolysis in Wood under Elevated and High Temperatures

Li,

Xu,

Chen

et al. 2024

Buildings

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Thermal responses of wood significantly depend on the dehydration and pyrolysis processes. However, the dehydration and pyrolysis of wood are not well understood. In this study, the thermal model of wood, considering the temperature-dependent thermo-physical parameters, was presented. Differential scanning calorimetry (DSC) experiments were conducted on the Douglas fir wood with different moisture contents to validate the apparent specific heat capacity submodel. Subsequently, the thermal model was, respectively, implemented in the finite element software Abaqus 6.14 and finite volume software OpenFOAM 5.0 to simulate the three-dimensional temperature profiles within the wood. Dehydration experiment was conducted on the Douglas fir wood to verify the thermal model from room temperature to 200 °C. The thermal model was further validated by the full-scale fire experiment of the cross-laminated timber panel made of Spruce wood. It was found that both latent heat and pyrolysis heat have significant influence on the apparent specific heat capacity which further affected the thermal responses of wood. Moreover, the temperature is more sensitive to the latent heat than to the pyrolysis heat. The gas velocity is rather low in the dehydration and pyrolysis stages due to the low gas pressure. As a result, the gas convection seems to have very limited influence on the temperature progressions.

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Section: Thermal Conductivitymentioning

confidence: 99%

Section: Thermal Conductivitymentioning

confidence: 99%

Experimental and Three-Dimensional Numerical Investigations of Dehydration and Pyrolysis in Wood under Elevated and High Temperatures

Li,

Xu,

Chen

et al. 2024

Buildings

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show abstract

“…It intends to compile design formulas for further discussions and enhancements to structural safety of wooden beams under thermal and mechanical loading conditions. The authors of this work have published different articles in conferences and journals related to this theme [12][13][14][15]. They studied other wood species to analyze the evolution of charring rate using experimental and numerical methods.…”

Section: Introductionmentioning

confidence: 99%

Structural safety in wooden beams under thermal and mechanical loading conditions

Fonseca¹,

Coelho²,

Barreira³

2012

Int. J. SAFE

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The main objective of this paper is to identify different analytical methods which permit the calculation of the stress level in wooden simply supported beams, due to mechanical and thermal loading conditions. Two different wood species, with different cross-sections, will be presented. The fi re resistance, the charring depth layer and the charring rate will be determined using the fi nite element method with Ansys® program. To characterize the stress state in wooden beams, all elements are subjected to mechanical load considering the reduction of the cross-section, infl uenced by thermal action. Another purpose of this work is to identify the ultimate safe load-bearing capacity in wooden beams, subjected to uniform load simultaneously with the thermal effect. All numerical results permit the specifi cation of simple design calculation methods, simplifying the verifi cation of the fi re safety of wooden beams. Keywords: charring depth, fi re, load-bearing capacity, uniform load, wooden beam. Fonseca et al., Int. J. of Safety and Security Eng., Vol. 0, No. 0 (2012) ABSTRACTThe main objective of this paper is to identify different analytical methods which permit the calculation of the stress level in wooden simply supported beams, due to mechanical and thermal loading conditions. Two different wood species, with different cross-sections, will be presented. The fi re resistance, the charring depth layer and the charring rate will be determined using the fi nite element method with Ansys® program. To characterize the stress state in wooden beams, all elements are subjected to mechanical load considering the reduction of the cross-section, infl uenced by thermal action. Another purpose of this work is to identify the ultimate safe load-bearing capacity in wooden beams, subjected to uniform load simultaneously with the thermal effect. All numerical results permit the specifi cation of simple design calculation methods, simplifying the verifi cation of the fi re safety of wooden beams.

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“…It intends to compile design formulas for further discussions and enhancements to structural safety of wood beams under thermal and mechanical loading conditions. The authors of this work have published different articles related to this subject [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Analysis of simply supported wood beams at ambient and high temperatures

Fonseca¹,

Gouveia²

2018

IJET

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The main objective of this work is to present a methodology for safety analysis of simply supported wood beams at ambient and high temperatures with a concentrated load at mid-span. Sixteen different beam configurations will be studied. All calculations were conducted according the Eurocode 5, part 1-1 and part 1-2. During this study will be analyzed the safe load bearing capacity according standards and compared with the elastic and plastic load from beam theory. The beam theory can provide sufficient accuracy up to the point of instability. The standard methods are generally conservative and they are suitable to be used for design purposes with safety. The studied beam cross sections will be in glued laminated wood, as yellow birch, with characteristics equals to a Glulam GL28H.

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High temperatures in parallel or perpendicular wood grain direction: a numerical and experimental study

Cited by 4 publications

References 7 publications

Experimental and Three-Dimensional Numerical Investigations of Dehydration and Pyrolysis in Wood under Elevated and High Temperatures

Experimental and Three-Dimensional Numerical Investigations of Dehydration and Pyrolysis in Wood under Elevated and High Temperatures

Structural safety in wooden beams under thermal and mechanical loading conditions

Analysis of simply supported wood beams at ambient and high temperatures

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