Today in History - April 15, 1912 – The Titanic sinks after colliding with a massive iceberg three hours earlier. There were over 2,200 passengers and crew aboard for her maiden voyage from England to the United States. Only 705 survived. At the time of her construction it was the largest ship every built and the builders claimed the ship to be the safest ship in the world – so what went wrong? On September 1, 1985, oceanographer Bob Ballard and his crew found the wreckage of the Titanic about 350 miles southeast of the coast of Newfoundland, Canada. Since then several expeditions have uncovered fragments of the ship that have been used to reconstruct and perfrom a forensic investigation of what actually happened.
There are many theories and some claim that if only one of these operational or engineering failures had not occurred the Titanic would not have sunk. Engineering student Vicki Bassett does a good job of summarizing the many theories the Virginia Tech’s Engineering Review. My colleague Roger McCarthy has an interesting video of his perspective from a failure analysis conducted by Exponent. His video from the History Channel points to the low quality of the steel and the substandard rivets.
Another colleague of mine from Yale, Ainissa Ramirez, has an exciting TED talk (photo above left) on material properties to get students and the public excited about engineering. She did a video demonstration for Scientific American (photo above right) in honor of the Titanic anniversary. She speculates the that the frigid temperature around the iceberg may have made the steel more brittle and the rivets less strong.
Naval Architects Richard Woytowich and Roy Mengot have reconstructed the failure from photos of recovered pieces and interviewed survivors. They created a computer model of a portion of the bottom structure in order to identify weak spots, as shown in the image below. They hypothesize that the failure began in the ship’s bottom structure when the ship was at a 17 degree angle. They also point to the rivets as being the weak points - because of the way the hull was riveted together, the bottom was not as strong as most investigators believed. And because of the way the uppermost strakes (strips) of plating were constructed, they had much more strength than most investigators have given them credit for. They discount the previous prevailing argument that the failure started at the upper edges and high stresses around the deckhouse expansion joints as they claim: The deckhouse was made of lightweight plating, and carefully constructed so as NOT to share in the structural loads on the ship.
On the 100th anniversary of the Titanic disaster I can’t help but reflect on the responsibilities of the manufacturers and engineers involved. Today it is important that engineering educator’s work with students to learn from engineering failures in order to prevent them in future.
For more information, see the Engineering Pathway’s resources on the Titanic and Engineering Failure Analysis. For related educational resources, visit the Mechanical Engineering, Naval Architecture and Marine Engineering or the Ocean Engineering disciplinary communities.
Also on this date in 1923 is the first commercial insulin.