Re: Determining balsa stiffness

From: markdrela <drela_at_mit.edu>
Date: Sat, 14 Jan 2006 19:00:43 -0000

--- In Indoor_Construction_at_yahoogroups.com, Don Slusarczyk
<don5490_at_s...> wrote:
>
> I mean the weight of the sheet causes too much delfection. 1 sheet of
> .020 thick by 1" wide by 18 " will significanylt deflect due to its
> own weight. You can not apply any weight to it or it will break.

In that case I would shorten the spacing between the end supports
until the self-sag is acceptable. It doesn't take much reduction in
the spacing to greatly reduce the self-sag.

You are then measuring the stiffness of only the wood that's between
the supports, but that seems OK to characterize the whole length of
the sheet. Variation across the grain is another matter, of course.
Received on Sat Jan 14 2006 - 11:03:02 CET