You may or may not be mixing two stories. :>)
The Titanic's alloy suffered from temperature related embrittlement that
lowered the impact strength of the metal at the relatively high
temperature of the North Atlantic on a winter night. Had the water
temperature been higher, the ship may have been able to shrug off the
iceberg impact. This is speculation, since we are not sure how hard the
hit really was. Designers at that time knew next to nothing about impact
strength and how temperature altered it.
The Liberty ship plates popped open while they were in operation. One
split in two while it was docked. No undue stress was put on them at
all, just the stress of supporting their own weight and slicing through
the water. I was taught in school that this was due to a phenomena
called stress risers and lamellar tearing. But see below.
http://www.fema.gov/library/351ch2.pdf has more than you'd probably want
to know. Answers some of the OPs questions. Briefly mentions the Liberty
Ships on Pg. 2.
Now this page literally throws cold water on my statement by stating
that the Titanic and the Liberty ships suffered from the same fate.
http://www.disastercity.com/titanic/index.shtml Not exactly a scientific
journal, but interesting all the same. Yes they did fail, Roger, I'm not
sure where you got your information that they didn't.
Type the words ["liberty ships" failure stress] into google and you will
get a bunch of hits explaining the problem.
Jon Rush
Mechanical Engineer P.E.
Derek Harling wrote:
>
> Were the welded Liberty ships the ones where the welds broke in the cold
> of the North Atlantic? Or was that another story altogether?
> Derek (vague memories of college lectures on materials and welding)
>
> >At 17:41 9/16/2001, Roger Gibbs was inspired to say:
> >
> >>When Kaiser Steel was building ships during WWII, they moved to welded,
>rather
> >>than riveted construction. Competing ship yards claimed riveted
>construction
> >>being more robust, with a slight ability to give before failure. The Kaiser
> >>Liberty ships and Aircraft Carriers (small ones) never failed (other than
> >>torpedoes) as far as I know.
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