Question

Question 2:
“The RMS Titanic was an Olympic-class passenger liner, launched for the
first time in 31 May 1911. The ship’s steel was “probably the best plain
carbon ship plate of the time”. Nevertheless, shortly before midnight on 14
April 1912, four days into the ship’s maiden voyage, Titanic hit an iceberg.
The impact caused the hull to fracture and water poured into the ship, sinking
it two hours and forty minutes later. Of the 2223 people on board, only 706
survived. Most of the victims died of hypothermia in the icy -2°C Atlantic
waters between Southhampton and New York, the destination, where the
ship sank. There are many factors that contributed to the sinking of the ship;
one of the primary reasons being metallurgy of the ship’s hull.”

Explain why even if engineers had tested the steel hull’s material properties
at room temperature, they still would not have predicted failure when taking
the impact of the iceberg in the icy Atlantic waters into account. Also,
describe how the steel should have been tested.

Answer 1

For manufacturing of the hull the 3 most important properties material should have are :

1. High Ductility : large deformation without fracture

2. High Toughness: ability to absorb large energy due to strain  without fracture

3. High strength : ability to withstand high stress without failure.

With decrease in temperature though the strength remains almost unchanged, ductile and toughness decreases considerably. In other words we can say the material becomes brittle as the temperature decreases. Thus its ability to absorb large impact energy and produce plastic deformation decreases. The ship material was tested at room temperature and the results were used for designing. They didn't take into account the change in ductility and toughness with temperature.  As the temperature was low The striking of the iceberg produced high impact stresses and the material cracked without producing any plastic deformation. This contributed towards shrinking of the ship.

we generally test the material for its properties  at room temperature and elevated temperature for normal engineering application. Judging the situation that the ship will be at icy cold situation the test should have been also carried out at the the minimum temperature of operation.

hope the answer is clear to you and it helps your understanding. ??. Best wishes.