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Calibration of a constitutive model for diffusive moisture transport in wood using data from X-ray CT-scanning and digital speckle photography

Jonas Danvind ; John Eriksson (Institutionen för konstruktionsteknik, Datorintegrerad konstruktionsmekanik) ; Håkan Johansson (Institutionen för konstruktionsteknik, Datorintegrerad konstruktionsmekanik)
5th Conference on Timber drying for value-added prducts, COST action E15 "advances in drying of wood" p. 210-218. (2004)
[Konferensbidrag, övrigt]

An unsteady-state diffusion model is applied for studying wood drying below the fibre saturation point. The moisture diffusion coefficient in Fick's law for Norway spruce under isothermal drying conditions is determined. Using X-ray CT-scanning and Digital Speckle Photography, the wood density and moisture content are obtained in the radial direction of the wood samples. An optimization scheme is used to minimize the difference between observed and computed moisture content in order to calibrate the values of a set of parameters describing the diffusion coefficient. In this study the values of the parameters for a parameterization of Arrhenius' type are determined. The general idea discussed, however, is not limited to a specific model, but can be used for a wide class of parameter identification problems. The results show a good agreement between observed and computed moisture content and it is concluded that the numerical realization of the optimization scheme works well. Nevertheless, the value of the diffusion coefficient is somewhat higher than expected. This is likely the consequence of a permeable coating of the samples.

Nyckelord: calibration, diffusive moisture transport, CT-scanning, wood drying



Denna post skapades 2006-09-28. Senast ändrad 2014-09-29.
CPL Pubid: 1285

 

Institutioner (Chalmers)

Institutionen för konstruktionsteknik, Datorintegrerad konstruktionsmekanik (1900-2004)

Ämnesområden

Samhällsbyggnadsteknik

Chalmers infrastruktur