[indoor_construction] B siffness

From: Slobodan Midic <slomi_at_EUnet.yu>
Date: Tue, 17 Jan 2006 22:08:20 +0100

>How's that for being scientifically unscientific?
>Bruce

Make a small tube, glue edges together, push corcs from balsa
in both end (glue ), and test both: bending deflection under weight
(horizontally) or vertically push the tube on scale up to crash,
or up to some preset force. Than you can calculate
stiffness exactly, for thinnest sheet (if you know formulas).

I don't test stiffness of thin C balsa sheets at all; I measure only
specific
weight, measure the thickness at more points, and regard the sheet
structure (light across the sheet), and as last I slightly
pressure the tube between thumb and forefinger to see if exsiste
some pure points. If the tube is not "good" I make a new tube
(but I have no very high criteriums, here the thin C sheets are
pearl, and than come 2, three, or four boron fibers). With 4 boron
fibers allmost all C sheets are good.

SM
Received on Tue Jan 17 2006 - 13:08:36 CET