Titanic

Discovery Channel : " Who Sank the Titanic "



Many theories tried to explain the reason causing the Titanic sinking. This episode made me fascinating is about " Mechanics of Material ", " Material Science " . They tried to demonstrate the flaw of rivets punching into the hull of the Titanic that lead the ship vulnerable in the freezing temperature.



Water tight compartments. Each compartment can be isolated and sealed off to contain flooding
in the advent of emergency.

The vast hull of the Titanic is designed to be watertight by overlapping steel plates and three million rivets drilled them using the hydraulic machine.

But the hydraulic machine is so cumbersome, it could be used only on the stretch sections of the ship.



At the curve area of the bow, they have drilled rivets manually.

But the steel rivets is too tough to hammer in.

So instead they used iron rivets which are more malleable. This could potentially weaken the small area of the bow section.


The New York Times : In Weak Rivets, a Possible Key to Titanic’s Doom.

Each of the great ship under construction required three million rivets that acted like glue to hold
everything together. The scientists argue that better rivets would have probably kept the Titanic afloat long enough for rescuers to arrive before the ice plunge, saving hundreds of lives.


Even thought the Titanic is the latest luxury liner, it isn't just carrying millionaires. Many are third-class passengers immigrated to the United States in searching the new life.











The damage suggests that may be something wrong with seams. " The Quality of Rivets ".

To find out what those rivets were made of and how that materials were acted on the different
mechanical tests.





Using the iron rivets rather than steel are explored.

The section of Titanic hull is reproduced. They compare the " Iron Rivet "  to " Steel Rivet ".

The test replicates the amount pressure of Titanic hull endured during the collision. As the iron rivets fail under the pressure of iceberg, they snapped off. The Titanic hull opened like the zipper allowing the huge amount water to gush in.



The iron rivets is 30% weaker than the steel, but it is still strong enough to hold the hull together.

Electron Microscope

Slag in the iron rivets.

Slag can actually strengthen the iron in one direction, but it can weaken them in the opposite
direction (perpendicular direction).

These slag particles had potentially to made the rivets brittle and prone to fracture.

When the iron rivets were hammerer into the place, the slag particles have 90 degrees angle.
It creates the weakness at the head of rivets.











Arizona's  bow after her 1879 collision with an iceberg.

No one could imagine the iceberg collision rising above the bow.

It was recommended that in the future, the number of lifeboats should be enough to all passengers
on board.

[Highlights]
Iron Rivet (Slag)  and Steel Rivet.

[Questions]