Granite Material in WUFI2D

Kruti · Post by **Kruti** » Wed Nov 10, 2010 12:27 am -1100

I am a new user of WUFI pro and 2D. In WUFI 2D from the available material database when Granite was selected, pop-up window with the following message comes up." Granite: Moisture Storage Function , water content not ascending and in Liquid Transport Coefficient ,Suction water content not ascending. This might cause unexpected results".
Due to this error result graphs shows the same amount of water content through out the 3years of calculation periods. Do anyone knows how to change water content values ascending. Is that anything I can do to get result right?

Christian Bludau · Wed Nov 10, 2010 1:54 am -1100

Hallo,
the reason is that the moisture storage function of the material is not steady increasing. If you edit the material you will find the following list in the moisure storage function:

x="0,0" y="0,0"/>
x="0,432" y="4,93"
x="0,576" y="6,39"
x="0,753" y="6,56"
x="0,843" y="8,03"
x="0,9" y="9,1"
x="0,96" y="11,8"
x="0,9897" y="17,8"
x="0,9926" y="23,5"
x="0,9956" y="23,4"
x="0,9989" y="25,0"
x="1,0" y="50,0"
As you can see the value for 0,9956 is smaller as the last one. We have to correct this. At the moment the best way to corrct will be deleting the complete line.

Hope that helps,
Christian

Kruti · Post by **Kruti** » Wed Nov 10, 2010 11:39 pm -1100

Hi,
Thanks for the reply. I have deleted the complete line from the moisture storage function of the granite, however still the water content is not showing any increase or decrease from 1st to 4th year of duration. Do you think this is right, as the porosity of the garnite is quite low (0.095m3/m3)

Christian Bludau · Thu Nov 11, 2010 1:59 am -1100

Yes, this is right... granite is a very tight material, so the water content should only increase really slow. The granite from the database was an old one, quite many pores for granite and it already was weathered.
Here you can see a picture of the specimen:
http://www.irb.fraunhofer.de/denkmalpfl ... att=Granit_
Additional please control your boundary conditions, especially the heat transfer coefficient. If this is 0 you may have no chanche in the construction as well....

Kruti · Post by **Kruti** » Thu Nov 11, 2010 3:13 am -1100

I have set heat transfer coefficient to 17 for external surfaces, so that might not be the reason. I agree that this type of results may be because of granite being very tight material, as I have tried the same thing with sandstone and I can see the increase in water content.
thanks for your help

Christian Bludau · Fri Nov 16, 2012 3:32 am -1100

Hello Kruti,

we found out, that there is an error concerning the granite in the MASEA database. The values were measured at another research institute.

The a-value is about factor 10 to high.
Please change water absorption coefficient from 0,086 to 0,0086 kg/m²s0,5

We will fix that in the next database update...

Best regards,
Christian