Hello Walter,
BCS wrote:
Hello Walter,
BCS wrote:
Every engineering discipline I have any experience with gets a heck
of a lot closer to producing formal proofs of correctness than
programing.
Mechanical engineering designs also tend to be a lot simpler than
programs, although the environment they work in is far more complex.
Modeling for the design analysis also takes a very simplified view
of the actual design, justified by taking the worst case. For
example, the strength calculations are done for the weakest cross
section, and are not bothered with for the obviously stronger
sections.
Now days they just jump to using finite element and compute
everything.
I still see calcs submitted for approval that are done by hand on
paper.
If you want to see real seat of the pants engineering, look at one of
those hot rod shows like Musclecar. I don't think those guys have ever
even seen a calculator.
and anyone who knows what they are doing should be able to clean up... but
where's the fun in that.
Furthermore, after a while a good mechanical engineer develops a
"feel" for things that is pretty darned accurate. Going through the
analysis is a backup
No, the analysis is mandated, by code if not law.
Not much. Even for buildings, only a few critical spots need checking.
This is possible because building structures are usually way
over-designed, because it's cheap and convenient to do so. Where every
gram counts, like in a spacecraft, everything is analyzed.
Mostly they avoid doing detailed analysts by reducing thing to already solved
problems: i.e. they do what the building code says or look up the accepted
values or follow the best practices.
These sources can be treated as theorems: under conditions X, Y and Z if
you satisfy constraints A, B and C, things don't break. Thus we have design
by modus ponens.
I once had a fire hydrant installed on my property. The city required
an engineering analysis, which ran to quite a stack of paper. After
approval, the workers came by to install it. They never looked at the
analysis, or even the drawings, they just dug up the water main and
stuck a hydrant on it with a specialized tool they had. Done in an
hour or so.
I'd almost bet that buried somewhere in the fine print of the "engineering
analysis" was the assertion "the standard way works" or the same things in
10 times the words.
--
... <IXOYE><
