Dear fellow researchers,
I have a question concerning numerical modelling of moisture flow in wood.
According to literature (Siau and Avramidis, 1995; Fortino Mirianon, Toratti 2009), the moisture flow at the surface of wooden body is expressed by using the following equation:
qn/ro=Su* (u air - u surf)
where qn is moisture flow across the boundary, Su is the coefficient of surface emission, u surf is the moisture content of wooden surface and u air is the equilibrium moisture conent of wood, corresponding to the air humidity, ro is dry wood density.
From the experimental testing, surrouding air relative humidity and wood surface moisture content are known. From the literature, diffusivity coefficients for orthotropic wood are known.
According to literature, unit for surface moisture flow is [kg/ m2s], according to Abaqus documentation - mass diffusion analysis - unit for surface concentration flux is [m/s], similar to the literature but with the density [kg/m3] omitted.
My question is: how to properly model wooden moisture surface flow in Abaqus, using mass diffusion analysis and how to use/set the right units doing that?
I thank you all for your help in advance.
With kind regards, Uros Gantar.
Here is how I added the surface concentration flux to loads in abaqus:
I determined tabular values with time and corresponding surface concentration flux in excel and implemented them to Abaqus through "Amplitutude - Tabular".
Hi Uroš Gantar,
Abaqus uses volumetric concentration, so you can take into account the density of the material in the post-processing of your data. By doing this you should have consistent units between literature and FE simulations.
I hope that this helps. Good luck with your work.
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