The OceanGate Titan submersible, the first deep-sea vehicle with a hull made primarily from carbon fibers, recently imploded in the Atlantic Ocean, resulting in the loss of five crew members. Experts, including Arun Bansil, a distinguished professor of physics at Northeastern, are investigating the possibility that the vessel’s experimental carbon-fiber hull, constructed in a mere six weeks, might have been a key factor in the disaster.
The OceanGate Titan submersible imploded in the Atlantic Ocean, causing the death of five crew members. Investigations focus on the experimental carbon-fiber hull, a first in deep-sea vehicles, as a possible cause. While carbon-fiber composites offer advantages like light weight and high strength, their ability to withstand deep-sea pressures is not well understood, highlighting the need for further research and testing in such applications.
With the debris of the OceanGate Titan submersible now in the possession of authorities, investigators are hard at work piecing together (literally) what caused the vessel to implode in the Atlantic Ocean more than two weeks ago.
Northeastern Global News already spoke to Arun Bansil, university distinguished professor of physics at Northeastern, to try to gain a better understanding of what exactly might have happened all those fathoms beneath the surface, where the five Titan crew members died.
One potential explanation has been widely discussed: the vessel’s experimental carbon-fiber hull, which the company turned around in just six weeks, according to one report.
Northeastern Global News tapped Bansil again to provide a brief overview (and history) of the use of carbon-fiber materials in deep-sea watercraft. The conversation has been edited for brevity and clarity.
Arun Bansil, university distinguished professor of physics, poses for a portrait in the ISEC building. Credit: Photo by Matthew Modoono/Northeastern University
There’s been a lot of chatter about the Titan submersible’s carbon-fiber composition. Can you explain why carbon-fiber material might not hold up as well as titanium, aluminum, and steel under deep-ocean pressure?
For components requiring light weight and high strength, carbon fiber-based composites have been successfully developed for use in aerospace, automotive, sports, medical, and consumer industries.
When it comes to deep-sea applications, however, this is not the case, and steel, titanium, and aluminum are used widely for making pressure hulls.
Titan was the first deep-sea vehicle with a hull made mainly from carbon fibers. The ability of carbon fibers to withstand repeated cycles of stress, especially compressive stress, under deep-sea pressures is not well understood, making it difficult to design safe hulls based on carbon fibers.
The degrading effects of water absorption on the epoxy binding the carbon fibers in the composite should also be kept in mind in assessing the failure of Titan.
When did carbon fiber begin to be seen as a candidate material for these types of watercraft?
It seems that adventurist Steve Fossett started exploring the use of carbon fibers around 2000 for the hull of a one-person submersible to dive to the bottom of Challenger Deep, which is the deepest point in the Mariana Trench, at about 36,000 feet.
The submersible DeepFlight Challenger that Fossett commissioned has not been tested or deployed. Titan was the first deep-sea submersible with a carbon-fiber hull.
Why are companies experimenting with these new materials, and are there other alternatives that have shown promise?
New materials are the backbone on which transformative science and engineering advances are made. Carbon fibers offer many advantages over metals, such as high strength, lightweight and corrosion resistance.
Titan had made several dives to the Titanic shipwreck, and we should withhold judgment on the primary trigger for its implosion until the ongoing investigations are completed.
My guess is that researchers will eventually develop carbon-fiber-based materials for deep-sea applications, along with testing protocols for safe operation of the submersibles.
what part of carbon being geometrically compressible into diamond layer compact-ability eludes engineers to the point of choosing to NOT perform catastrophic testing before exposing humans to the cavity being subjected to such pressure extremes…this reeks of phumdukkery and oversight enforcement consisting of and defined by kneepad/toothbrush methodologies. People Died Losers!
The carbon fibers were under heavy compression but fibers are for tensile strength. Modern pressure tanks are wrapped in fiber and resin because the outward pressure is pulling the material apart. The tensile strength in the carbon fiber was no help in the compression environment of the sea. The shell of the sub was built for a jet plane with a pressurized cabin.
That is my thinking too. Great tensile strength, less for compression.
Carbon fiber materials are woven, not rigid. They’re designed to give, not resist. Kevlar vests, for example, are soft armor, meaning they bend to dissipate the force of an impact. Building a deep sea hull with such material is foolish in the extreme.
There is some mention of “The degrading effects of water absorption on the epoxy binding the carbon fibers”.
Another factor is the slow hardening of thick layers of epoxy — My guess is that 6 weeks was not long enough for the epoxy to reach full strength — covered with water or not.
These liberals thought that on high seas the engineering rules of construction doesn’t apply, that their company can do anything they want out of the jurisdiction of their country, and they did, see the results. This is the problem of the liberals, they want no regulations and no rules for the companies, this is why the world is polluted and a lot of other issues like this!
Nice job trying to bring politics into this, but you may want to check your source about which party is the party of less regulation.
It’s OK, autocorrect sabotages my writing occasionally as well.
Jason, you are right! I mean conservatives :)) But at the point of view of the industry and companies, the conservatives are liberals in term of regulations (no regulations, companies can pollute or do whatever they want). Thanks for correction.
I thought it was conservatives who are always harping about the need to de-regulate. Trump, Bush, all of them on that constant theme. Trump wanting to dismantle Clean Air Act. What about the trains?
This is science not politics. Jason is correct.
They’ll find an air bubble in a layer of that hull. It’s hard to get all the air out even with a vacuum. From there it will become a cycle based fatigue lifespan. CF isn’t all that great with transverse rupture strength.
Note: given the fact that details of how the carbon fiber composite was processed are unknown by me, it is difficult to conclude what caused of hull failure, however, the following are appropriate comments in a general sense.
I would refine your “air bubble in a layer” to …. the carbon fiber/ resin hull in all probability contained a high level of porosity (micro voids). The porosity is a result of many contributing factors e.g. amount of pressure applied prior to matrix (resin) gel point, the matrix composition, the form of carbon fiber used (unidirectional a’la filament winding, woven fabric), etc.
It is highly probable that cycling a hull made without aerospace -like composite processing to repeated dives could develop areas of micro-cracking which is structurally unacceptable.
In any case, the selection of carbon fiber composites for deep sea applications without the rigors of testing certainly is living in ignorance.
I’m honestly confused about the need for any of this. With OLED technology, there is no need to travel all the way to the titanic. There is enough footage to build a absolutely convincing simulation, even out to sea. Go in the sub, go deep enough to loose light, have the simulation take over, all while hovering at what, 200 300 feet? Even throw in some mechanical creaks to instill a small amount of fear.
No one needs to be the wiser.
Reference Dr. Bansil’s comments – he leaves out any detail or explanation about the Steve Fossett 2000 exploration – he states that carbon fiber was used in Fossett’s submersible – it would be instructive to know details – how did it perform?
HE STAYTED THE CRAFT WAS NEVER LAUNCHED
Thanks for the input – I missed this explanation
*STATED
Was there a total weight limit on the Titan submersible’s crew and baggage? There are undocumented reports of unusually rapid descent, then very slow ascent when mission was scrapped to attempt return to surface.
SciTech Daily has gone downhill in its presentation style and the ads are killing it for me. It used to be well-written summaries with simple illustrations. Now it has had a bad attack of the nerds, aided and abetted by advertising of stuff that is a waste of money.
Um hum.
The article doesn’t even attempt to present any test data… We should have someone with an Instron doing at least a simple test with 4-week hardened sample. Arun could have quoted any tests… Like this…
https://www.sciencedirect.com/topics/materials-science/carbon-fiber-properties
All very interesting. It seems as though Stockton Rush needed more scientific research before he launched Titan.
The use of syntactic foam would have been more practical to increase buoyancy. This could have covered a titanium shell properly designed to resist pressure. A cylinder does not resist external pressure well and as it gets longer in proportion to its diameter so the reinforcing problems compound. A sphere is much easier to make but not really as hydrodynamic for speed
This article provides 0 updated information and the amount of adds makes for a really annoying read!!
My engineering (BSME and 39 years experience) tells me the makers of the Titan likely cannot lay claim to having “designed,” the vessel in a rigorous manner. Epoxy exhibits “creep” under stress and time. Creep means the material takes on a new shape due to the squeeze force, and it does not return to the original dimensional shape when the stress forces are removed. Secondly, carbon fibers are useful in resisting tension, but an individual carbon fiber will have no benefit to offer in compression; therefore, it is questionable as to whether the carbon fibers even in their great numbers can significantly enhance the structural properties of the epoxy. In other words, without a great amount of materials testing, the designer might not be sure which material is the main source of strength, the carbon fiber or the epoxy. Another issue is whether the carbon/epoxy matrix develops microscopic cracks as it is compressed by the water pressure. If it does, the sea water will intrude into the matrix with some unknown and perhaps adverse effects. Further, if I were involved, I would be highly concerned about whether the modulus of elasticity is greatly different for the two materials. I suspect that is the case, and if so, would that cause disbonding of the fibers from the epoxy as the structure is flexed by the water pressure? Also, how much air is in the epoxy itself, and how much air is carried into the product matrix by the fibers as they are introduced?
Regarding: “carbon fiber will have no benefit to offer in compression” (A) and (B) “structural properties of the epoxy” ****
(A) I have to presume you are unaware of Boeing and Airbus applications of carbon fiber composites for secondary as well as for primary structures. If your statement had any credibility, the above-mentioned manufacturers would have never used carbon fiber composites.
(B) the contribution of epoxy in a caron fiber composite is miniscule compared to the structural contribution of carbon fiber.
BSME and 39 years experience – experience in what?? good grief!!!!
At best, carbon fiber hull would be a limited thing… Something used for a finite period, then discarded.
But my cardboard mansion was built on sand painted with water based paint to make it firm…
Why would anyone build a machine or device for use by humans that could possibly injure or kill without any testing on it for safety prior to it use , regardless of the type of materials used or the knowledge of those materials used. There are too many variables in places like space and deep in oceans factors we can only know about by testing. I would even question aluminum in the deep as it is overall a soft metal that bends easy and with little memory – unlike stainless steel or titanium. Obviously something wasn’t done correctly
The comments here have been largely informative…Thanks! As an explanation, the epoxy resin is only partially cured when impregnated into the CF…when it is time to form the part, pressure and heat are applied to the sheets of CF/epoxy to cure it into its desired form. The epoxy will cure over time in storage…at some point there will be insufficient material to get the multilayer cure when it is time…this is why Rush’s remark about it being expired is interesting….
Article did not address what the title suggested. The comments were actually more informative than the article itself. Thank you to commenters for posting.
To those indignant of zero oversight from government and industry, regulation, you missed the obvious. OceanGate operated outside maritime laws by operating physically beyond jurisdiction of USA and Canadian maritime borders where Titanic is located. This effectively allowed OceanGate to legally bypass accepted testing and certification standards long ago established to address implosion issues. OceanGate is the only company refusing non destructive testing of its pressure hull. All other submersibles were tested and achieved certification for deep dives, resulting in zero fatalities. I did notice in recovery videos at least one partially covered titanium end cover (of two) appeared to be intact, suggesting metallurgy survived the implosion. Without seeing the other end cap and lookout window, there may be speculation of possible window, seals and/or carbon fiber shell failures under high compressive forces.
I this guy approached me to take the trip I would laugh at him carbon fiber weakens in bike frames over time the material is medial in technology at best its also used in European super cars as well that’s were it belongs this guy was a loose nut
Regarding carbon fiber: “that’s were it belongs”
1. If “this guy”
2. where it belongs
3. Ever heard of Boeing and Airbus and their use carbon fiber in primary structural applications??? Suggest you have knowledge about a subject prior to pontificating about it.
Very true unuseful interview. No data