After the wreckage of Titanic reappeared, the scientific investigation team collected metal samples for analysis, and found the important details that led to the sinking of Titanic: shipbuilding engineers only considered increasing the strength of steel, but did not think of increasing its toughness.
By comparing the metal fragments of the wreckage with the current shipbuilding steel, it is found that the current shipbuilding steel can bend into a V shape when it is hit in the water temperature of the sinking site of the Titanic, while the steel on the wreckage will break quickly due to insufficient toughness. The cold brittleness of steel is found, that is, at the temperature of -40℃~0℃, the mechanical behavior of steel changes from toughness to brittleness, which leads to catastrophic brittle fracture.
However, steel made by modern technology will become brittle only at -70℃~-60℃. But we can't blame the engineers at that time, because no one knew at that time that adding a lot of sulfide to steel-making raw materials in order to increase the strength of steel would greatly increase the brittleness of steel, which led to the tragedy of the sinking of Titanic.
A team of marine forensic experts analyzed the rivets on the salvaged Titanic hull, and found that the rivets fixing the steel plate of the hull contained unusually many glassy slag particles, which made the rivets very fragile and easy to break. This analysis shows that under the impact of icebergs, it may be that the rivet broke, which led to the disintegration of the hull, and finally the Titanic was buried at the bottom of the Atlantic Ocean.
According to a new study by Tim Mardin, a British historian, an unusual optical phenomenon-a mirage-is the reason why the Titanic crashed into an iceberg and failed to get rescue from nearby ships. 1992, a survey by the British government showed that the sinking of the Titanic might be related to superrefraction, but this possibility was not explored until Mardin studied the weather records, survivors' testimonies and long-forgotten nautical logs.
Mardin found that that night, the atmospheric conditions in the sea area were prone to superrefraction, and the light was abnormally bent, thus forming a mirage. This phenomenon was also recorded by several ships in the nearby sea area at that time. Mardin said that a mirage prevented the observation deck on the Titanic from finding the iceberg in time, and also prevented the cargo ship California from identifying the Titanic and communicating with the ocean liner.
Extended data
Disaster is coming
19 12 April 14, Sunday night, a calm night, not even a little wind. If there is, the crew will find the little scales of the waves lapping on the iceberg. Titanic sailed at a speed of 22.3 knots (about 45 kilometers per hour) on this dark and cold ocean (the maximum speed was 23 knots). Captain Smith ordered the lookout to observe carefully after receiving ice reports from many ships nearby.
Because it was a warm winter this year, icebergs drifted farther south than in previous years. However, the crew of Titanic couldn't find the telescope (because the only pair of binoculars on board was locked in the cupboard by the second mate at that time, and the second mate who kept the key of the cupboard didn't get on board at last), so the lookout had to observe with the naked eye.
At 23: 40, the lookout Frederic fleet (who survived later) found a black shadow "the size of two tables" in the distance, which became larger at a rapid speed. He knocked the alarm bell on the bridge three times and grabbed the phone: "There is an iceberg directly ahead!" " . The six Moody's who answered the phone informed the next Murdoch.
Murdoch immediately ordered the bell to ring: "All engines slow down! Left full rudder! No.3 propeller reverses! " It was only 37 seconds after the lookout found that the iceberg hit the starboard side of the ship, when the Titanic was less than 400 meters away from the iceberg.
The first mate immediately ordered two orders, full rudder left and full propeller emergency backward. Later, it was proved that this order was a fatal mistake. Just 37 seconds after he ordered it, the Titanic couldn't stop moving forward and turning in time because the hull was too big, the rudder was too small and the forward speed was too fast, and the starboard side of the ship slammed into the side of the iceberg.
23: 40: Due to the violent impact, the rivet on the starboard bottom of the bow was knocked loose and disconnected, and the waterproof partition was partially cracked. Numerous tiny but narrow cracks appeared in the first five cabins, and seawater poured in continuously. Then the waterproof gate was closed in time, and all the bilges became 16 mutually independent watertight warehouses.
23: 50: In the first 10 minute after the hull hit the iceberg, the water level rose from the keel 14 feet, the first five cabins at the bow began to be flooded, and the boiler room No.6 was covered by the water level of 8 feet. At this time, more than 4000 tons of seawater have flooded into the bow, but the seawater is blocked by waterproof boards. The situation seems to be fine, and everything seems to be under control.
Captain Smith came in from the crew's cab and asked what had happened to the crew. After learning what had happened, the captain immediately ordered all the engines in the ship to stop working. The Titanic slowly stopped at the silent center of the North Atlantic, and the captain then called engineers to repair the damaged parts.
23: 55: The result of this collision was later known to people. But at that time, the passengers and crew in the cabin reacted differently. Some passengers who didn't sleep well in first class and second class were awakened by a slight metallic scraping sound, and the hull shook slightly. Some people think that there is a big wave, some people think that they are on the rocks, and some people think that the propeller has failed.
But the passengers in the cabin below felt the vibration much more violently. Some passengers saw the milky white iceberg passing by outside the starboard porthole. Some ice blocks that were hit by the ship and wiped off the side of the iceberg fell onto the right deck of the bow.
The immigrant passengers on the ground floor were even more shocked to find that the icy seawater was overflowing the door and pouring into the bedroom from somewhere, and the ship quickly stopped. Some passengers in the cabin are familiar with things, put on their coats and take their own things to leave the cockpit and come to the deck. The stars are shining over the North Atlantic, and the temperature is as low as MINUS one degree (because the North Atlantic has just passed a long and cold winter).
Under the dark sky, the window of the Titanic gave off a warm yellowish light. All the boilers in the ship stopped working, and the four tall yellow and black smoke pipes and chimneys on board exhausted a lot, making a huge noise. Three of them suddenly gave a deafening roar and screams.
Passengers who know the steam engine know that it is the boiler safety valve on board that releases excess superheated high-pressure steam. After a while, the passengers on board and inside the ship resumed their activities.
0: 00: At this time, more than 7,000 tons of seawater has flooded into the bow, and the water has flooded a fore-bow tip cabin, three bow cargo cabins and No.6 boiler cabin. The seawater overflowed from the top of the submerged watertight compartment and began to flood into the third-class cabin, further covering the upper H deck. The bow began to slowly sink, and the fate of sinking was actually doomed (at that time, the maximum tolerance of the watertight compartment of Titanic was four, while the part of the cabin that was flooded)
A large number of workers in the No.6 boiler room are trying to eliminate stagnant water. The crew reported to Captain Smith in the control tower that the water had flooded the fore cabin, cargo holdsNo. 1, No.2 and No.3 and boiler room No.6, and he immediately asked designer thomas andrew to evaluate the damage.
After some evaluation and calculation, Andrew then concluded in the master's room that "the ship is hopeless" and said that the ship could only last 1-2 hours, and the captain asked all the crew to release the lifeboat immediately. At that time, the position where the ship stopped was 4 1 46 minutes north latitude and 50 degrees west longitude 14 minutes.
Baidu Encyclopedia-Titanic