On 10/27/2013 12:30 PM, woodchucker wrote:
....

So how is yellow glue capable of high stresses structurally but not in
bent laminations? I would think the stresses structurally would be
subject to creep to and therefore lower the structural value.

But only bent laminations are devalued.. I understand that bent
laminations are under constant stress, but we don't know what or how the
glue is used structurally. Imagine a bench that someone sits in 16 hours
a day... two shifts... is'nt that under a similar stress?

The difference is that in the bent lamination example there's residual
stress (and quite a lot) of the bent material trying to return to it's
original shape. This is constant and unrelenting; hence over time the
plasticity begins to show.

In the bench there's some intermittent loading but there really isn't a
comparable load between the glue joints that is continuous nor in the
tangential direction that is there as the difference in lengths in the
curved lamination.

--