Extruded Polystyrene (XPS)

[rxcomposite]

Originally Posted by groper

RX,

in your point 1, i dont think this is correct. heres why...

Using the formula from beam theory, where core stress = F/h*b
F= P/2 for simply supported and fixed both ends, panel loading.
P= applied load
h= panel thickness
b= panel width

You can see that the modulus of the skins is nowhere in this formula, therefore has no effect on the shear stress in the core.

You should not limit yourself to simplified formulas as there are more sophisticated formulas available to predict composite performance.

If you will search this forum, you will find that a lot have been discussed about composites.

[groper]

ive spent 30mins searching the forum and google.... i still cant find anything that suggests skin modulus will have anything but an infinitesimally small influence on core shear stress. This is the reason it is ignored along with many other things in simplified equations, we also combine this with a few assumptions for sandwich structures. We are well within these boundaries for our discussion purposes here...

[rxcomposite]

Well good luck to you if you insist.

[brian eiland]

Originally Posted by gabdab

Reply from Finnfoam.
Should I use the skin on non skin type :

Another reply from Finnfoam when I made a recent inquiry as to whether their product was available in USA?

Our product is not available in USA but similar product is. If You are specially interested in our product F-700, comparable product by Dow Chemicals is Styrofoam Highload 100 (blue board). Our F-700 has short term compressive strength 700 kPa and Dow declares 690 kPa for Highload 100. I don’t know what kind of blowing agent Dow uses in USA but that shouldn’t have significant relevance in this kind of use. We use CO2 as blowing agent, so our board cells contain air.