Engineering vs Seat of the Pants

[RicB]

Hi folks

One thing that keeps bothering me and makes it difficult to resist 
buying right into the RC & S gangs reasoning is that we never hear 
anything about how
compression reliant boards  figure load bearing.. or much of anything 
else for that matter.  I find all kinds of references to how an RC & S 
board is actually designed... but nearly nothing about how one figures 
basic things like just how darned strong a CC board is. 

It struck me the other day that perhaps there isnt really much to begin 
with, that perhaps this all was started by a more seat of the pants 
approach.  If you dry a panel you can judge its MC fairly accuratly by 
knowing the beginning MC and how much it shrunk after drying ... yes ?  
So.. reversing that logic if you have a dried panel and inhibit by some 
mechanism it from expanding and you know how much increase in RH you 
subject it too... then you know how much compression the panel has taken 
on.  Ribs are a way of inhibiting this expansion yes ? Seems to me then 
that measuring the amount of crown, knowing the bending strength of the 
ribs, and the change in RH gives you then enough information to fairly 
accurately find the strength of the assembly for any given amount of 
crown. From that point perhaps a few decades of trial and error with 
regard to problems incurred with various rib placements designs was more 
significant in terms of <<design>> then any engineering in the usual 
sense of the word.

Ok.. this is pure speculation on my part.   But it would REAAAAALLLLY be 
helpful if someone would do a basic review for the benifit of the whole 
list as to how one goes about designing (by the book... if there is one) 
a CC board, or any board that relies very much on compression.  It would 
most certainly make it much easier to see  <<the light>> as it were 
between the various methods of building boards.

I've done two board replacements earlier... and got quite a bit of 
advice as to rib placement / size... etc... and both these were reliant 
on compression for crown... and no one could really give me any good 
specific engineering reasonings for any of their advice.

Cheers
RicB