: Hi there, Hank.

: Thanks for trying, but I may be even more confused. If it's true that:
: "[t]he wood strength is not critical in this type of construction
: construction because the wood serves primarily as core for the fiberglas.
: The fiberglas is the grain-it provides the strength."

: then how do you interpret the clear differences in the strip panel test
: results where the panels deflected more, and failed at, lower forces when
: the force was applied parallel to the grain than when applied at right
: angles? Every other factor was factored out, correct? The only difference
: was the orientation of the wood grain.

: Am I imagining the wrong kind of test machine? I thought the 3-point test
: machines applied a straight knife-like force to the middle of a test
: coupon supported at each end. Like if you had an 8'- 2"x4"
: supported by saw horses 8' apart, and you start stacking bricks on it in
: the middle.

Pete,

You are correct. Our tests clearly demonstrated that the wood contributed to the strength of the samples. The difference in loading behavior with grain orientation clearly showed this.

Your description of three-point bending is also correct - but the three supports were cylindrical rollers. The center roller had a diameter of one inch, and the two end supports had one-half inch diameter rollers.

Sam