"Tom Francis - SWSports" wrote in
message ...
On Thu, 4 Dec 2008 12:07:32 -0500, "Eisboch" wrote:


"Richard Casady" wrote in message
. ..
On Wed, 3 Dec 2008 11:28:46 -0800, "Calif Bill"
wrote:

The problem with lots of the aluminum ship structures was bad design.
Lots
of cracks happening. So better designers were needed. Harry maybe?

Actually, since aluminum and steel have the same strength to weight
ratio, it would seem that someone heard rumors that aluminum is
lighter, and designed it that way. Lighter is weaker. Duh.

Good grief.

Use steel in the places you need strength.
Use aluminum in the places you need light weight.
Use titanium when you need both.

I'm not an expert on steel or aluminum, but a few years ago I had to
do some research on this very subject.

As I understand it, and again this is remembering what I learned at
the time, the major difference between steel and aluminum is that
aluminum will reach it's failure point, given the same strength
standard, 40% sooner than steel.

Again, that's how I remember the issue.

I could be entirely wrong.

There is no cycling rating for aluminum It will eventually crack if flexed.
Where as steel has a rating (B10?) where if the metal is not flexed beyond a
certain point will last forever.