WHY IN NEWS ?
- The four-day-long search for the missing Titan submersible has come to a tragic end.
- Reports have confirmed the vessel was subject to a “catastrophic implosion” at some point during its voyage towards the Titanic shipwreck.
WHAT IS TITAN SUBMERSIBLE ?
- Titan is a submersible, or an underwater vehicle.
- It is operated by the privately owned U.S. company OceanGate that organises underwater expeditions for both research and tourism.
- The company claims that Titan, which it said was built with “off-the-shelf” components, is lighter and more cost-efficient than other deep diving submersibles.
- The 6.7-metre-long manned submersible is intended for “site survey and inspection, research and data collection, film and media production, and deep sea testing of hardware and software,” according to the OceanGate website.
- The company said its expeditions were meant to document the Titanic and its rate of decay on the ocean floor, and that all expeditions were in line with National Oceanic and Atmospheric Administration (NOAA) Guidelines.
WHAT IS CATASTROPHIC IMPLOSION ?
- Submersibles and submarines operating at depth have a pressure vessel made of a single metallic material with high yield strength.
- A titanium or thick steel pressure vessel is usually a spherical shape that can withstand the crushing pressures you might expect at 3,800m – the depth at which the Titanic wreck lies.
- Titanium is elastic and can adapt to an extended range of stresses without any measurable permanent strain remaining after the return to atmospheric pressure.
- It shrinks to adjust to pressure forces, and re-expands as these forces are alleviated.
- A carbon-fibre composite, on the other hand, is much stiffer and does not have the same kind of elasticity.
- A composite material could potentially suffer from “delamination”, which leads to a separation of the layers of reinforcement.
- This would have created a defect which triggered an instantaneous implosion due to the underwater pressure.
- Within less than one second, the vessel – being pushed down on by the weight of a 3,800m column of water – would have immediately crumpled in from all sides.
- All five passengers on board the missing Titan submersible are believed to be dead.
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SOURCE: THE HINDU