"Tom Veatch" wrote:

Your point about the assumptions underlying the model is well taken.
The simplifying assumptions are rarely a true and exact picture of
the
real world. That's why it's called "Engineering Approximation" and
why
"Safety Factors" (civil engineering) or "Margins of Safety"
(aeronautical engineering) are always applied to any critical stress
analysis.

The most dominant design factor is the eyeball.

It's got to look good in the shower.

Look at the columns on some of the monuments in Washington DC.

Ever see a school building with anything smaller than an 8WF35 floor
beam.

Still remember my design engineer's comment about bracing ribs on the
bed of a threading machine used in a steel mill to thread seamless
drill pipe.

"I could use 3/4 thick ribs, they are certainly strong enough, but
1-1/4 ribs look better, and after all, we sell this equipment by the
pound".

Lew