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This is what the defense industry cutely refers to as "retroactive qualification". That is: performing the environmental simulation testing to qualify component suitability AFTER having field deployed the product to the field. I remember in 2015, UTAS needed to qualify some small transformers to MIL-STD-202. Got a test lot soldered down to a piece of perf board, put them through shock and vibration tests. Between each sequence they needed to be bench tested and measured values recorded. Following moisture resistance testing, and average of 2 out of 5 pairs of coils were found to be open, affecting each transformer. UTAS sent us new test lots, now two boards with transformers. This went on for months. Eventually we had UTAS engineers and military brass in the lab. Absolutely everything they could think of to test was tested, especially stuff that might make the failures our responsibility. Well, as it turns out, after root cause analysis was performed, it was found that the resin used to fill the void space within the package body surrounding the delicate windings was reacting to the +125°C half cycles of the moisture test, which produced chlorine gas. The chlorine, now sealed in with extraordinarily fine copper wire, just ate right through it. I imagine the out gassing occurred on the first hot half cycle, and each hot half cycle thereafter accelerated the oxidation process. Most of the time, for such jobs, we don't have any idea what the components are being used in, only that the end customer is the government. A little birdie did eventually reveal that these transformers were for the flight control surfaces for the Patriot PAC-3. Why all the desperation? Well, the PAC-3 batteries had already been manufactured, shipped around the globe, and forward deployed by several ally nations. The cost of a forced recall would have been astronomical. Many millions of dollars, affecting billions in product. It seemed the lowest bidder on those transformers didn't use the epoxy stipulated by MIL-PERF, and used something else instead. Better late than never, when it comes to simulation and testing...I guess.
@@YawnGod don't think so, not controlled information, just incompetence. But no worries on contractors part, the gravy train keeps flowing to do the job right the second and third time.
That wouldn't have helped. You're still crushing things that are meant to be expanded against for stress loading. There is a way to shape a hull so that continuous filament winding would have worked fine, but it's not as simple as "reinforcement ribs" on a cylinder.
As far as engineers testing their own creations, I have no issue with that. "He chose... poorly". The thing is when you take along others that don't fully understand the risk and then get killed. That's the thing I have an issue with.
@@d_lollol524My father in law recently died in a godforsaken age care facility that failed him immeasurably, now that was gruesome. The poor old guy literally asphyxiated due to pneumonia. The occupants of this sub were probably scared knowing things were going bad but would not have suffered physically.
@@d_lollol524 No, would have been impossible, the rapid compression of the air in the sub would have turned the inside of the crew compartment into an incinerator many times the temperature of the sun for a split second, so there would be nothing left of them, save for a few chunks of skin that may have been ejected far enough away to be spared from the incineration. And all of this would have happened faster than they could've processed what they were seeing and feeling, so they saw and felt nothing. One second they were there and terrified, the next second they were nothing.
hindsight; i don't understand why they made this so damn huge: build 10 identical small conventional sphere shaped titanium submersibles, all 10 remote operable but also capable of taking one passenger. take 3-4 of them down at the time in a "convoy", whether the people operating them are up top or down under really doesn't matter. if anything happens, you have 6-7 others on standby all capable to reach to the bottom of the ocean, each with any sort of prying, cutting, winch or any other implement you'd need to help the stranded one(s) out? it would have been just as comfortable, and 3 people doesn't share the same tiny window, they have one each for themselves. we have technology for remote operation of submersibles, we might as well use it? even off road car people don't often go with just one car, because it's always good to have the help of another one that isn't currently in the mud.
You're expecting people who are basically tourists to be able to perform either assistance to, or rescue of a disabled submersible at 13,000ish feet under the ocean. That's a bit of a stretch, I'd say.
i may have worded something wrong@@Name-ps9fx but that's not what i meant at all. the people piloting the things would still be professionals. the guests would only get control if they wanted it. but the real point is, as small a passenger cabin as you can get away with, and with remote operation, absolutely no need to cram multiple people into the same one
Terrible idea. You just introduced a lot more failure points. The titan design as it was, could easily have been fixed. The easy fix would be same design but with a titanium cylinder. And even the carbon fibre cylinder could probably have worked if done properly.
I've suspected that the pressure vessel failed beginning at the glued end rings and this simulation seems to support this idea. When I first saw how little purchase the end rings had on the CF cylinder it was obvious that all the strength would have to be in the glue joint with no support from being inserted into the titanium rings. When the cylinder started to compress just a little that bending would pry the glue joints apart leading to rapid failure. It would have been stronger if the end rings had been much deeper to extend the glue joint and lend support under bending force. Oh well...too late now.
unfortunatly I am not glue expert, would like to know if there are some rule of thumb guide on how deep the interface rings should be for a glue connection
@@hnrwagnerThat is a very good question that I am unable to answer with any certainty. But considering that any cylinder exposed to great external pressure is going to deflect in the longest unsupported area first...which means the center....this deflection then uses the length to the glue joint at the end to apply a leverage on it trying to pry it from the outermost edge inward. The Oceangate cylinder fit into the end rings what looked like less than an inch...which would be little better than just a flat glue joint relying totally on the adhesion without any mechanical assistance holding it together. There is an engineering concept called 'Belts and suspenders' where when possible you also add a mechanical connection to help hold the glue...and vise versa. Considering where this thing was going I was expecting to see at least 6" deep surround of the joints by the end caps...which certainly would have made them much more expensive but the added glue surface as well as the support of the surrounding metal ring would have made the joints much stronger. They obviously didn't think this was needed...they were wrong.
I can't really imagine glue joint being structural, after all the forces do act vaguely across the connection. It's in turn a possibility that the deformation of the CF cylinder against the end rings was the cause of failure of the CF cylinder as a whole, starting from the ends.
That was my 1st instinct as well. I was more focused on what the thermal expansion rates of the titanium, the epoxy, and the carbon fiber materials used and how they compare to each other. If there's any significant difference between them, a lot of stress would be built up in the joint as the submersible descends/ascends causing differential cooling/heating of the different materials relative to each other.
yes, the rear hemisphere deformed a lot in the simulation, There could be a number of reasons, the assumed geometry of the support beam, the assumed material but also the C3D8R elements (had a few simulation with terrible hour glassing). model is still not perfect but we are getting there
@@hnrwagner what is causing the failure in your simulation? The Titan had several sucessful dives before the infamous last one, meaning that by design, the structure should handle the external pressure in a simulation, unless you account for some weaknesses somewhere caused by the multiple dives. Knowing that their CFRP shell was: - made from expired prepreg, - not cured in an autoclave, - reportedly making sounds of breaking fibres in previous dives, - notoriously difficult to test and simulate for compressive failure, I would assume that you overestimate the compressive strength of the CFRP shell in the last dive, hence why your titanium end caps deform, when in reality they didn't.
Regrettably the souls onboard basically vaporized, that's the only good thing to come out of this situation. I suppose that the confidence level of the passengers had in this technology limited their fear of the true danger of the extreme depths they were going to encounter. Maybe the fact that most average people understand that this was too dangerous and wouldn't even try to attempt to go on a ride in a vessel like this one.
It took me a while to understand that cfrp is not suitable for those depth for reasons which i will explain in a later video, not really sure that average people understand what this pressure differential does to you, it is really terrifying
Some commentary over the simulation would be nice to explain what we are seeing. Also the cones were retrieved, did they have any deformation similar to that in your video?
Good point, can do a description of what is Happening in a future Video, the Domes were recovered but not really any Informationen on their condition is available
I was asking myself the same thing. I would assume those end caps would have some deformation looking at this simulation, but taking their form, thickness and the materials into account it wouldn't surprise me if the deformation would be so slight that you'd only find it by actively looking for it. (Looking using a known real flat surface)
@@hnrwagner I've only seen the front hemisphere which isn't deformed in any visible way, not certain on the rear hemisphere. However the acrylic window was missing from the front hemisphere so that might have blown out.
Great work. I can picture that bond-line being replete with imperfections. Not mated exactly square, bubbles/voids/inclusions in the adhesive, etc. Bad idea.
I can't speak on marine grade structural adhesives, but from the aerospace perspective something like Hysol EA 9309 should get you ballpark mechanical properties for a medium-high strength composite to metal bond. Often times a scrim cloth layer is added to maintain a minimum bond-line thickness but I didn't see anything like that in the Titan footage. Looking forward to your study!@@hnrwagner Now I'm wondering about structural adhesives at extreme cold temps 😬
@@mer9706 bro they used some kinda thick ass epoxy paste applied in a dark ware house with like trowels. it was not even a mix gun and it was cleaned with a acetone rag. Try whole part ultrasonic submersion followed by a god damn plasma chamber and used with a mild vacuum mixer (you need to mix thick epoxy under mild vacuum and dispense with a cylinder), applied by technicians in a well lit clean room with bunny suits on and full recording of the glue being applied etc. Their shit looked exactly like high end hardware store PC-4 epoxy, useful for something like fixing PVC to pipe for wood in a DIY radio prototype. I think they even mixed it by hand in the video, and applied it while on a step ladder in what looked like a generic storage warehouse.. That shit was like a total joke, it would be OK for gluing together a investor mockup made out of plywood. Not that I would trust it anyway if they did all the glue steps, I think it needs to be made with solid forged titanium. The video I saw makes me think the bond was total shit. I just forget if they were applying it upside down too. they had a brick layer do that shit. And I don't recall something impressive being used as the cleaner either, I would at least opt for a fresh bottle of ultra pure acetone from sigma thats tested for oil inclusions and stuff. Like open it right before use from the storage tin AFTER taking a small sample for independent analysis of cleaning agent. there was a youtube video about it on their channel like right after the accident. dank ass facility looked suitable for working on old fork lifts
@@cdrom1070 I agree lol. I was just thinking in terms of design intent based on middle of the road structural adhesive properties. Their actual execution is obviously another matter entirely. I'm more curious about how the design holds up on paper/simulation and whether it was ever feasible, regardless of the actual procedure seen on video.
Nice work Dr. ! My opinion and two cents for further improvements. First, I believe there are 3 or 4 steel beams or square tubes connecting the rings together running along the carbon tube, I wish I could be more precise but by the time I find the right videos things will have moved on. Second, the collapsing tube and the domes collapsing towards each other... Now I don't know the limits of the program and what it can account for and what it cannot account for, but I believe that when the tube collapses that the program does not seem to account for the high pressure water filling the void at the same time that it is crushing the tube, because I believe that this action will interfere with the domes collapsing towards each other. Like they might start to move towards each other at the beginning of the collapse (milliseconds) but will hit the collapsing water in milliseconds also, and this water also has the force of the implosion with it. Also the beams mentioned earlier will also hold back the domes somewhat Don't know by how much, but it is interesting to note that just like the window they seem also to have been blown clean off. Maybe unlikely but just maybe the beams managed for a few milliseconds to hold back the domes just long enough for the implosion to first cancel the crushing force from the domes and second to blow them clean off along with the window ? And finally, I think you are working on this, about the glue joints, and because also we know that their wasn't any carbon left on the recovered domes... you may find some formula to determine the approximate strength of that bond but I believe that in this case you could forgo or disregard it completely and let the simulation run it's course without any force "gluing" or holding the carbon and the titanium together and I think the simulation will show pretty much what happened in reality. Meaning that during the implosion the force was so that the glue had no chance of holding on to the titanium and could not and did not actually apply force on the titanium, it could not even prevent the carbon from moving sideways and brake the lip (40mm lip). So for this reason again I think that if you simply (in your simulation) put the carbon tube on the rings without any bounding parameters (just touching) that this would be close enough to reality, the forces are simply to great for that bond to make any significant difference. Looking forward to more of your fine work !
I am researching for more info on the lateral beams or tubes.. I'm commenting right now because it is easy to see at least the 2 beams on each side (still looking to confirm the others) and the main reason I'm commenting right now is that there is an easy proof that the side beams and the others (once confirmed) that the beams stay with the sub when the skid frame is jettisoned... The white "skin" prevents the beams from going anywhere, The skin is also bolted to the beams so they are not jettisoned along with the skid frame. Other components are also in the way, like the side thrusters. And also there is the video that shows the skid's that have been recovered, one of them is missing a leg, they of course are not bolted to the side beams. And I must also add that the steel cylinders drop weights carrying apparatus is affixed to the side beams, I have to verify if that apparatus can be jettisoned completely or in part I do not believe it can, but of course the are completely separate from the skid frame.
There is evidence for a beam at the top, I'm still looking for a beam at the bottom, maybe they chose not to put one because of the drop weight system ? The beams are secured by 3 bolts at both ends unto rectangle lugs welded to the rings..
@@michelalphonso6945 I would like to add water to the simulation but I do not know if it is even possible in the way you describe to consider it. Cannot consider bolts in any way than the calculation time goes through the roof, it is already nearly a week for this model (on our University computer). I am looking to add more details to the model in the future like the beams you have described
@@hnrwagner I understand, we can't have everything unfortunately. About the beams, I believe there are only 3, and I could not get a close look at the top beam, but from what I saw it looks different (modified) from the side beams, The 2 ends of the top beam (about 2 Ft ) look intact meaning fully there, but the middle part seems to have been cut in half along the length, (the side facing the tube) why ? weight saving, making room for wires, ? That beam does not have to support anything heavy like the side beams do. I have seen a view from the top, and the skin is continuous at the top (no split) with only 6 bolts spread apart a few inches in the middle section, attaching the skin to the top beam. So the side beams are the main beams and their main purpose is to support the under drop weight system, and secondarily used for an attach point for the skin. I do not believe that their main role is securing the rings. The close up of the side beams seem to show a significant gap between the beam and the attach points at their ends, (maybe there's a thick rubber gasket) which makes some kind of sense as I think you don't want the beams to interfere with the rings pressing on the tube during the dive making the glue joint "secure". So what do we call that, semi-floating beams ? For the water, I wonder if there is a program or a calculation for the explosive force (implosion) ? It's unfortune you can't include all you want, but hey your playing with the absolute limits and that's something right.
Just stick with what works. Make a series of titanium spherical hulls, each self contained for one passanger each, with self contained life support systems, emergency beacons, and all. Have the rest of the system (engines/navigation) be in a structure surrounding the spheres, mounted underneath the capsules to keep the weight aimed down for balance, as well as to be out of the way incase the habitat modules need to eject, like what the Alvin used.
@@hnrwagner Can you state something about possible precursers of the implosion? Looking at the results it seems very self-reinforcing, in other words it seems that a nearly infinitesimally small crack propagates to full size catastrophy within miliseconds. Or again in other words, the often mentioned alarm system was only snake oil for feeling a little safer. Do you follow these maybe naive impressions?
Not sure if you have a good enough program for simulating applied stresses of a tapping or hitting the structure while under pressure. You can have a depth rating for a vessel, but seals and structure ratings change when bumping the vessel occurs. That's why metal is preferred being it's less prone to change.
I recommend using an audio editing tool to apply a "de-esser" effect to your voice; something about your microphone, environment, or voice causes the s sounds to be very sharp/harsh.
Incredible analysis and simulations. I wonder if the same could be done for Polish TU-154 crash on 10 April 2010 near Smolensk in Russia, with 96 killed.
I have a question: Are the material properties for the used titanium and CFC known? Specifically the "bulk modulus"? Because since I heard about that tragedy I was wondering whether the titanium domes contracted at a different rate than the CFC tube and hence creating shear stress in the dome-tube interface.
Very interesting, and rather chilling. The only consolation to be had is that, for those inside, what happened was so sudden and so devastating, they never knew what hit them.
I ask myself , did they really dont know that something bad is going to happen or did they? If the soul leaves the body, does it think, damn that was unexpected?
@@hnrwagner I choose to believe, the latter. Not so unusual on the face of it, as sudden death for human beings has often taken that basic form. You're minding your own business, then WHAM. Not something that can be proven scientifically, anyhow.
This model predicts significant deformation in the end caps. From what little has been shown in the press, the end caps seem to have remained largely the same shape however. Also one would expect the bolts holding the end caps and the interface rings together to be a major structural failure point. Are they even modelled in this simulation?
As shown in the video, the material of the endcaps is not known, it was probably more sturdy than assumed. The bolts cannot be modelled, geometry is not known, material is not known and even if nobody would model them. This model took a week in terms of computation time, if one would consider the bolts, it would probly take weeks or even month
That looks like a very good static load based simulation .. The inertia and accleration of water does not seem to be present. The speed of sound in the composite is much faster than water so as shown the cylinder shatters and then the water accelerates inwards ( generating a powerfull negative going pressure shock wave propergating away from the summarine) but draging the acilillary stuctures inwards with the inrushing water . The weight of hemisphers will slow up the axial inward progress of the water pushing them. However when the now very fast moving water fills the hemispheres there will be a huge positve pressure spike creating an outward moving destructive shock wave, this will blow a lot things outward inculding the window found some waqy from the submarine. I still hve not seen a convincing simulation that handles the water well .
This simulation takes about a week, with water physics this will probably explode in terms of computation time, also not really sure if it is even possible
@@hnrwagner I worked in the diesel fuel injection world with pressures regularly up to 3000 Bar . Because the smallest injection events are over in less than 0.5 milliseconds everything is shock waves. One further point that has been missed by all commentators is the impractical nature of trying to match the reduction of diameter of a cylinder to an abutting hemisphere as the pressure increases. In steel in both halves we never managed to do it. I predict to the failure started at the glued interface as in the unwanted shear force due to inbalanced deformations pushed the the composite over the edge.
When I saw the hemispherical ends shooting towards each other, I did wonder about the water rushing "in" to fill the space between them and how would that act against the inwards moving ends. My assumption was that the collapse was faster than the water can move.
Would be helpful to hear some simultaneous commentary during the failure simulation on where the failure was assumed to start, how it progressed, etc. It appears to start at the ends of the composite tube, perhaps at the interface with the titanium end rings. Was that because of modulus mismatch between the composite and the titanium? Or did the compressive stress on the composite end surfaces simply exceed allowables? What assumptions were made? How would the model change if, for example, the failure started in the composite tube away from the end rings, perhaps due to cumulative damage from multiple compressive cycles? The graphics are pretty, but in the absence of explanatory detail, it's difficult for viewers to interpret what they're seeing, other than the obvious depiction of a cylinder collapsing axially.
Carbon fiber is so hard to model. In my experience failed carbon fiber parts can retain strength in other sections, or in some directions but not the primary direction. Perhaps it failed in a way that kept the hemispheres from rushing in, preventing them from deforming.
does anyone know what aluminum cylinder they used for the inside to lay the fiber on? I was reading alot about airplanes and I read that anodized aluminum experiences sudden huge crack failure after repeated strain, unlike bare aluminum .Thats why some parts are treated with alodine and paint and why you can't just anodize everything on an airplane.
Wouldn't the two hemispheres shoot outward like a rocket rather than be forced inward? Also is it known if bottom weight skid was released or not based on alleged transcript? Weight skid was recovered and don't remember if it had noticeable bend inward as simulated here.
No. Hydrostatic pressure is isotropic, which effectively means all surfaces of the traction acting on the pressure boundary acts inward along the surface normal, even horizontally. For the end caps to shoot outward like your describing, the pressure in the interior chamber would have to somehow rise much higher than the ambient water pressure to expel the caps outward. There is no mechanism here that could cause that. If you are thinking about a jump rocket toy, this only works because the pressure you apply to the chamber by jumping on the bladder becomes much higher than the ambient air pressure acting on the rocket.
Google Scholar: scholar.google.de/citations?user=a4sKEKsAAAAJ&hl=en Researchgate: www.researchgate.net/profile/Ronald-Wagner OrcID: orcid.org/my-orcid?orcid=0000-0003-2749-1455 Timecodes: 0:00 - Introduction 0:16 - What we know and don't know about the TITAN 1:27 - The updated TITAN CAE model and its details 2:12 - The Pathway of Engineering 3:54 - Disclaimer 4:04 - Real-Time Implosion Simulation 4:10 - Implosion Simulation slowed by Factor 10000 4:33 - Simulation of Brittle Composite Cylinder 5:03 - Effect of Implosion on Leg-Support 5:29 - Effect of Implosion on Panels 5:49 - Effect of Implosion on Hemi-Spheres 6:14 - Implosion of TITIAN with different views 7:59 - Logarithmic Strains
I think number you are interested in is how fast the water comes in which at my best estimate around 180 mph. I don't know exactly because it depends how quckly and what the mass was of the shattering carbon fiber cylinder . Thye shock wave travels much faster and comunicates the change in circumstances to the surounding water. The first shock wave propergates AWAY from the vessel at the speed of sound in water at about 1550 m/sec ( 3467 mph) . On one side of the shock wave the water is stationary on the other side all intense pressure due to depth acelerates the water insantly towards the vessel at aprox 180 mph ( depends on the pressure drop accross the shock wave). When all these tons of in rushing water fill the void they have to stop like a hammer hitting an anvil ( any air bubles left will be very small and very very hot) . This causes tremendous pressure spike as the water then rebounds off itself and any solid structure such as the hemisphers creating a new shock wave propergating outwards. This is the really destructive one because one side of the wave the water is rushing inward the other it is rushing outwards this just liquidises things. I hope this helps you imagine what is going on .
Thank you for this awe inspiring structural simulation…it brought forth both tears of loss and tears of exhilaration by demonstrating that 2 @1/2 spheric End-Caps of sufficient uniform strength separated by a hollow tensile cylinder of insufficient compressive strength will collapse to form a compact sphere when subjected to sufficient external pressure. Brilliant >> Beer Can Compression 101
Recently I came across a guideline for manned submersibles which stated that you need at least a safety factor of 6 ,the titan had 2.25 from reports, so we now know 2.25 is too low
The AI pronounces Newfoundland wrong. Newfoundland is pronounced New-fin-LAND. I know that's not how its spelled but neither is the way the AI said it "new-fin-LIND".
It looks to me like the cfrp cylinder was the weak point, it appears to collapse in on itself pulling the two titanium hemispheres in towards each other as it collapsed .
Most likely no. Your guess is most likely partially correct except my guess would be that the carbon fiber, along with the occupants, were vaporized due to the rapid compression of the air heating the air to many times the temperature of the surface of the sun for a split second.
Wow. I know you wish this could be done on gpus...haha....Any thoughts on a 29 meter stainless steel 8 bar pressure tank/ship? ...if you want to get very popular...
not really sure what you mean with "29 meter stainless steel 8 bar pressure tank/ship"? you mean the ship which impacted into the bridge? thought about doing it but the geometry of the bridge is so complex. This simulation took 3 days on the university rig, and aborted countless times on the best part due to hourglassing, damn
Model is still not good enough after implosion happens, tried different titanium parameters but the calculation time is one week and this is the best I could come up with. Hopefully in a later model I get a better post implosion deformation
I dont understand why they made this submersible out of paper mache, Elmer's glue, aluminim foil, and popsickle sticks. Should have added some JB-Weld.
When this happened the guys at work started breaking down what happened and why. This was after a long pause of silence from everyone in the company after hearing the news.
@@hnrwagner They are submarine engineers. I could hardly follow with what they where saying when i was around. I still have a hard time following when they start going on about things lol.
Hi. As one that is working with one operating ear, the choice of voice is one that is mid-range, distinguishable in pronunciation of consonants and numbers, and overall intelligible in speech. note: hearing aids are a great invention, but they amplify all sounds including those annoying ones you have not heard in years, so not for me.
@@hnrwagner Why? Why not use your own voice, or just use a proper AI voice where the source voice is paid for, rather than copy an actual presenter's voice with AI?
@@hnrwagner yes, good point. Would it fall exactly where it detached, or shoot past it? Or sort of float a bit. Yep, it could be buried in the soft anywhere.
@@reginawagnerbiolife7867 Well, since I am actually able to read, I can see some videos have Digitally Generated warnings in the description, as TH-cam named them. The "learn more" would then take me to Disclosing use of altered or synthetic content on Support (dot) Google, where they list their guidelines for AI generated content. Plain and simple.
It still seems like an invalidating problem that you are simulating shells and not volumes. Why does it do that and how quickly can you change that and pretend this never happened?
@@hnrwagner it may be modeled as a volume but when it breaks it's just shells. Shells that go through each other when that shouldn't be possible. Like the rear dome top at 6:07 I don't know what the simulation is doing but it's certainly invalid after it starts breaking.
@@hnrwagner In the video multiple parts are shown independently and with different properties. That's a multibody. ¿did you simulate water and air in the outside or inside of the vehicle? Fluid-solid interaction is multiphysics. A compound of solids and a mechanical simulation is not multiphisics.
@@rtorresrtorres it's a structural analysis coupled with heat effects, didn't show the temperature evolution though it is questionable high, will show it later, fluid interaction is too expensive
@@hnrwagnerI am interested to understand the cyclic loading of CFRP. They were able to take it down a few times before it failed. Like you say though its brittle and there is no room for any sort of deformation it just splinters into a million bits.
I really hope someone didn’t pay to much for this simulation as it was not worth the time. What I mean is that the CEO of this was not worth the time. I feel for those he fooled into getting into that thing. But stupid is as stupid does.
In the 80's we called this a WAFWOT analysis... What A F'n Waste of Time. Bad input, bad simulation, meaningless output. And now it's posted on YT for pointless speculation. Yay science.
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That ad was Brilliant
This is what the defense industry cutely refers to as "retroactive qualification". That is: performing the environmental simulation testing to qualify component suitability AFTER having field deployed the product to the field. I remember in 2015, UTAS needed to qualify some small transformers to MIL-STD-202. Got a test lot soldered down to a piece of perf board, put them through shock and vibration tests. Between each sequence they needed to be bench tested and measured values recorded. Following moisture resistance testing, and average of 2 out of 5 pairs of coils were found to be open, affecting each transformer. UTAS sent us new test lots, now two boards with transformers. This went on for months. Eventually we had UTAS engineers and military brass in the lab. Absolutely everything they could think of to test was tested, especially stuff that might make the failures our responsibility. Well, as it turns out, after root cause analysis was performed, it was found that the resin used to fill the void space within the package body surrounding the delicate windings was reacting to the +125°C half cycles of the moisture test, which produced chlorine gas. The chlorine, now sealed in with extraordinarily fine copper wire, just ate right through it. I imagine the out gassing occurred on the first hot half cycle, and each hot half cycle thereafter accelerated the oxidation process. Most of the time, for such jobs, we don't have any idea what the components are being used in, only that the end customer is the government. A little birdie did eventually reveal that these transformers were for the flight control surfaces for the Patriot PAC-3. Why all the desperation? Well, the PAC-3 batteries had already been manufactured, shipped around the globe, and forward deployed by several ally nations. The cost of a forced recall would have been astronomical. Many millions of dollars, affecting billions in product. It seemed the lowest bidder on those transformers didn't use the epoxy stipulated by MIL-PERF, and used something else instead. Better late than never, when it comes to simulation and testing...I guess.
Thanks for sharing, very crazy and interesting experience
Does this count as whistleblowing or just blowing?
@@YawnGod anti-whistleblowing, i suppose
@@YawnGod don't think so, not controlled information, just incompetence. But no worries on contractors part, the gravy train keeps flowing to do the job right the second and third time.
@@YawnGodwhistleblowing after the game is over and both teams and the fans have left the stadium.
At least they saved $20000 of CEOs bonus by not adding those external stiffeners on the cylinder.
Still not sure what is better in this load case external or internal stiffeners, will try later ;)
That wouldn't have helped. You're still crushing things that are meant to be expanded against for stress loading. There is a way to shape a hull so that continuous filament winding would have worked fine, but it's not as simple as "reinforcement ribs" on a cylinder.
They saved a lot by the CEO being released of his job due to a sudden case of death.
ehhh, wouldn't have helped. in the end, the big core issue was them using carbon fiber which excellent in tension, is marginal in compression.
honestly, im all for every obscenely wealthy person going on just this sort of trip...
Fascinating, TY. A great pity this sort of work was not done long before any construction took place. RIP.
I wonder if they ever did some Form of simulation, eben simple would have helped
As far as engineers testing their own creations, I have no issue with that. "He chose... poorly". The thing is when you take along others that don't fully understand the risk and then get killed. That's the thing I have an issue with.
That is correct.
I get that reference…
The last part is soviet tank and aircraft engineering in a nutshell.
@@josecoronadonieto6911 And Soviet space engineering as well
For a brief moment, the crew all pulled together and became one.
Make them whole
a gruesome death. I wonder if any human body parts were found .
@@d_lollol524 Gruesome my @ss! They were litterally turned into "Red Mist" in less than the blink of an Eye.
@@d_lollol524My father in law recently died in a godforsaken age care facility that failed him immeasurably, now that was gruesome. The poor old guy literally asphyxiated due to pneumonia.
The occupants of this sub were probably scared knowing things were going bad but would not have suffered physically.
@@d_lollol524 No, would have been impossible, the rapid compression of the air in the sub would have turned the inside of the crew compartment into an incinerator many times the temperature of the sun for a split second, so there would be nothing left of them, save for a few chunks of skin that may have been ejected far enough away to be spared from the incineration. And all of this would have happened faster than they could've processed what they were seeing and feeling, so they saw and felt nothing. One second they were there and terrified, the next second they were nothing.
hindsight; i don't understand why they made this so damn huge: build 10 identical small conventional sphere shaped titanium submersibles, all 10 remote operable but also capable of taking one passenger. take 3-4 of them down at the time in a "convoy", whether the people operating them are up top or down under really doesn't matter. if anything happens, you have 6-7 others on standby all capable to reach to the bottom of the ocean, each with any sort of prying, cutting, winch or any other implement you'd need to help the stranded one(s) out? it would have been just as comfortable, and 3 people doesn't share the same tiny window, they have one each for themselves. we have technology for remote operation of submersibles, we might as well use it? even off road car people don't often go with just one car, because it's always good to have the help of another one that isn't currently in the mud.
That is actually a great ideal, thanks
That's not the shoddy engineering work we are going for with our company!
You're expecting people who are basically tourists to be able to perform either assistance to, or rescue of a disabled submersible at 13,000ish feet under the ocean.
That's a bit of a stretch, I'd say.
i may have worded something wrong@@Name-ps9fx but that's not what i meant at all. the people piloting the things would still be professionals. the guests would only get control if they wanted it. but the real point is, as small a passenger cabin as you can get away with, and with remote operation, absolutely no need to cram multiple people into the same one
Terrible idea. You just introduced a lot more failure points.
The titan design as it was, could easily have been fixed. The easy fix would be same design but with a titanium cylinder.
And even the carbon fibre cylinder could probably have worked if done properly.
I've suspected that the pressure vessel failed beginning at the glued end rings and this simulation seems to support this idea. When I first saw how little purchase the end rings had on the CF cylinder it was obvious that all the strength would have to be in the glue joint with no support from being inserted into the titanium rings. When the cylinder started to compress just a little that bending would pry the glue joints apart leading to rapid failure. It would have been stronger if the end rings had been much deeper to extend the glue joint and lend support under bending force. Oh well...too late now.
unfortunatly I am not glue expert, would like to know if there are some rule of thumb guide on how deep the interface rings should be for a glue connection
@@hnrwagnerThat is a very good question that I am unable to answer with any certainty. But considering that any cylinder exposed to great external pressure is going to deflect in the longest unsupported area first...which means the center....this deflection then uses the length to the glue joint at the end to apply a leverage on it trying to pry it from the outermost edge inward.
The Oceangate cylinder fit into the end rings what looked like less than an inch...which would be little better than just a flat glue joint relying totally on the adhesion without any mechanical assistance holding it together. There is an engineering concept called 'Belts and suspenders' where when possible you also add a mechanical connection to help hold the glue...and vise versa. Considering where this thing was going I was expecting to see at least 6" deep surround of the joints by the end caps...which certainly would have made them much more expensive but the added glue surface as well as the support of the surrounding metal ring would have made the joints much stronger. They obviously didn't think this was needed...they were wrong.
I can't really imagine glue joint being structural, after all the forces do act vaguely across the connection. It's in turn a possibility that the deformation of the CF cylinder against the end rings was the cause of failure of the CF cylinder as a whole, starting from the ends.
That was my 1st instinct as well. I was more focused on what the thermal expansion rates of the titanium, the epoxy, and the carbon fiber materials used and how they compare to each other. If there's any significant difference between them, a lot of stress would be built up in the joint as the submersible descends/ascends causing differential cooling/heating of the different materials relative to each other.
It would still be a faulty design on many other levels.
titanium material was assumed:
E = 140 000 MPa
yield strength = 840 MPa
if someone has clues for the material they used , this would be great.
well there's the real problem knowing what exactly they used in it's design
Thank you. Far beyond my comprehension.
What can i do to make it more understandable?
weren't the titanium hemispheres found intact? it looks like in this simulation they were deformend.
You are correct. They were found intact.
yes, the rear hemisphere deformed a lot in the simulation, There could be a number of reasons, the assumed geometry of the support beam, the assumed material but also the C3D8R elements (had a few simulation with terrible hour glassing).
model is still not perfect but we are getting there
@@hnrwagnerokay, thanks for the info
@@hnrwagner Run the simulation again with the skid mostly jettisoned such that only one leg of the skid is hung up with the sub.
@@hnrwagner what is causing the failure in your simulation? The Titan had several sucessful dives before the infamous last one, meaning that by design, the structure should handle the external pressure in a simulation, unless you account for some weaknesses somewhere caused by the multiple dives. Knowing that their CFRP shell was:
- made from expired prepreg,
- not cured in an autoclave,
- reportedly making sounds of breaking fibres in previous dives,
- notoriously difficult to test and simulate for compressive failure,
I would assume that you overestimate the compressive strength of the CFRP shell in the last dive, hence why your titanium end caps deform, when in reality they didn't.
Nice analysis models.
Thanks, really appreciated
The time it took for this to implode is unfathomably short
Brilliant! Can't wait to try it.
Regrettably the souls onboard basically vaporized, that's the only good thing to come out of this situation. I suppose that the confidence level of the passengers had in this technology limited their fear of the true danger of the extreme depths they were going to encounter. Maybe the fact that most average people understand that this was too dangerous and wouldn't even try to attempt to go on a ride in a vessel like this one.
It took me a while to understand that cfrp is not suitable for those depth for reasons which i will explain in a later video, not really sure that average people understand what this pressure differential does to you, it is really terrifying
Some commentary over the simulation would be nice to explain what we are seeing. Also the cones were retrieved, did they have any deformation similar to that in your video?
Good point, can do a description of what is Happening in a future Video, the Domes were recovered but not really any Informationen on their condition is available
I was asking myself the same thing. I would assume those end caps would have some deformation looking at this simulation, but taking their form, thickness and the materials into account it wouldn't surprise me if the deformation would be so slight that you'd only find it by actively looking for it. (Looking using a known real flat surface)
How did you get David Attenborough to provide the commentary? It’s great!
@@hnrwagner I've only seen the front hemisphere which isn't deformed in any visible way, not certain on the rear hemisphere.
However the acrylic window was missing from the front hemisphere so that might have blown out.
Why the AI voice? Your actual narration was mich nicer. This now seems random and low quality, when you're having the best public model of all!
If I do it myself, people complain my English is bad, if I do AI voice, people complain it is lazy and low quality, cant satisfy all I guess ;)
@@hnrwagnerat least when you narrate you don't sound out of breath. Please let David get some rest, you're working him far too hard.
@@hnrwagnerI don’t mind bad English. It’s probably better than those complaining and I’m not joking
Great work. I can picture that bond-line being replete with imperfections. Not mated exactly square, bubbles/voids/inclusions in the adhesive, etc. Bad idea.
I am working on another part where I will investigate this part in detail!
I can't speak on marine grade structural adhesives, but from the aerospace perspective something like Hysol EA 9309 should get you ballpark mechanical properties for a medium-high strength composite to metal bond. Often times a scrim cloth layer is added to maintain a minimum bond-line thickness but I didn't see anything like that in the Titan footage. Looking forward to your study!@@hnrwagner Now I'm wondering about structural adhesives at extreme cold temps 😬
@@mer9706 bro they used some kinda thick ass epoxy paste applied in a dark ware house with like trowels. it was not even a mix gun and it was cleaned with a acetone rag. Try whole part ultrasonic submersion followed by a god damn plasma chamber and used with a mild vacuum mixer (you need to mix thick epoxy under mild vacuum and dispense with a cylinder), applied by technicians in a well lit clean room with bunny suits on and full recording of the glue being applied etc.
Their shit looked exactly like high end hardware store PC-4 epoxy, useful for something like fixing PVC to pipe for wood in a DIY radio prototype. I think they even mixed it by hand in the video, and applied it while on a step ladder in what looked like a generic storage warehouse.. That shit was like a total joke, it would be OK for gluing together a investor mockup made out of plywood. Not that I would trust it anyway if they did all the glue steps, I think it needs to be made with solid forged titanium.
The video I saw makes me think the bond was total shit. I just forget if they were applying it upside down too. they had a brick layer do that shit. And I don't recall something impressive being used as the cleaner either, I would at least opt for a fresh bottle of ultra pure acetone from sigma thats tested for oil inclusions and stuff. Like open it right before use from the storage tin AFTER taking a small sample for independent analysis of cleaning agent.
there was a youtube video about it on their channel like right after the accident. dank ass facility looked suitable for working on old fork lifts
@@cdrom1070 I agree lol. I was just thinking in terms of design intent based on middle of the road structural adhesive properties. Their actual execution is obviously another matter entirely. I'm more curious about how the design holds up on paper/simulation and whether it was ever feasible, regardless of the actual procedure seen on video.
Nice work Dr. !
My opinion and two cents for further improvements.
First, I believe there are 3 or 4 steel beams or square tubes connecting the rings together running along the carbon tube, I wish I could be more precise but by the time I find the right videos things will have moved on.
Second, the collapsing tube and the domes collapsing towards each other... Now I don't know the limits of the program and what it can account for and what it cannot account for, but I believe that when the tube collapses that the program does not seem to account for the high pressure water filling the void at the same time that it is crushing the tube, because I believe that this action will interfere with the domes collapsing towards each other. Like they might start to move towards each other at the beginning of the collapse (milliseconds) but will hit the collapsing water in milliseconds also, and this water also has the force of the implosion with it. Also the beams mentioned earlier will also hold back the domes somewhat Don't know by how much, but it is interesting to note that just like the window they seem also to have been blown clean off. Maybe unlikely but just maybe the beams managed for a few milliseconds to hold back the domes just long enough for the implosion to first cancel the crushing force from the domes and second to blow them clean off along with the window ?
And finally, I think you are working on this, about the glue joints, and because also we know that their wasn't any carbon left on the recovered domes... you may find some formula to determine the approximate strength of that bond but I believe that in this case you could forgo or disregard it completely and let the simulation run it's course without any force "gluing" or holding the carbon and the titanium together and I think the simulation will show pretty much what happened in reality. Meaning that during the implosion the force was so that the glue had no chance of holding on to the titanium and could not and did not actually apply force on the titanium, it could not even prevent the carbon from moving sideways and brake the lip (40mm lip). So for this reason again I think that if you simply (in your simulation) put the carbon tube on the rings without any bounding parameters (just touching) that this would be close enough to reality, the forces are simply to great for that bond to make any significant difference.
Looking forward to more of your fine work !
I am researching for more info on the lateral beams or tubes..
I'm commenting right now because it is easy to see at least the 2 beams on each side (still looking to confirm the others) and the main reason I'm commenting right now is that there is an easy proof that the side beams and the others (once confirmed) that the beams stay with the sub when the skid frame is jettisoned... The white "skin" prevents the beams from going anywhere, The skin is also bolted to the beams so they are not jettisoned along with the skid frame. Other components are also in the way, like the side thrusters. And also there is the video that shows the skid's that have been recovered, one of them is missing a leg, they of course are not bolted to the side beams.
And I must also add that the steel cylinders drop weights carrying apparatus is affixed to the side beams, I have to verify if that apparatus can be jettisoned completely or in part I do not believe it can, but of course the are completely separate from the skid frame.
There is evidence for a beam at the top, I'm still looking for a beam at the bottom, maybe they chose not to put one because of the drop weight system ?
The beams are secured by 3 bolts at both ends unto rectangle lugs welded to the rings..
Another detail to consider, the fact that the implosion separated the domes from the rings !
@@michelalphonso6945 I would like to add water to the simulation but I do not know if it is even possible in the way you describe to consider it.
Cannot consider bolts in any way than the calculation time goes through the roof, it is already nearly a week for this model (on our University computer).
I am looking to add more details to the model in the future like the beams you have described
@@hnrwagner I understand, we can't have everything unfortunately.
About the beams, I believe there are only 3, and I could not get a close look at the top beam, but from what I saw it looks different (modified) from the side beams, The 2 ends of the top beam (about 2 Ft ) look intact meaning fully there, but the middle part seems to have been cut in half along the length, (the side facing the tube) why ? weight saving, making room for wires, ? That beam does not have to support anything heavy like the side beams do.
I have seen a view from the top, and the skin is continuous at the top (no split) with only 6 bolts spread apart a few inches in the middle section, attaching the skin to the top beam.
So the side beams are the main beams and their main purpose is to support the under drop weight system, and secondarily used for an attach point for the skin.
I do not believe that their main role is securing the rings.
The close up of the side beams seem to show a significant gap between the beam and the attach points at their ends, (maybe there's a thick rubber gasket) which makes some kind of sense as I think you don't want the beams to interfere with the rings pressing on the tube during the dive making the glue joint "secure". So what do we call that, semi-floating beams ?
For the water, I wonder if there is a program or a calculation for the explosive force (implosion) ?
It's unfortune you can't include all you want, but hey your playing with the absolute limits and that's something right.
Just stick with what works. Make a series of titanium spherical hulls, each self contained for one passanger each, with self contained life support systems, emergency beacons, and all. Have the rest of the system (engines/navigation) be in a structure surrounding the spheres, mounted underneath the capsules to keep the weight aimed down for balance, as well as to be out of the way incase the habitat modules need to eject, like what the Alvin used.
But that is boring;) better a not well enough tested proto cfrp death trap
The violence shown is incredible. At least they all went instantly.
not the worst way to go
@@hnrwagner Can you state something about possible precursers of the implosion? Looking at the results it seems very self-reinforcing, in other words it seems that a nearly infinitesimally small crack propagates to full size catastrophy within miliseconds. Or again in other words, the often mentioned alarm system was only snake oil for feeling a little safer.
Do you follow these maybe naive impressions?
@MrXenon1977 exactly, the system they had apparently registered cracking events.. which is absurd as a 'warning' device.
Damn Wagner, your work might be used in the investigation.
I am working on a documentary regarding this topic, should be ready in june
Not sure if you have a good enough program for simulating applied stresses of a tapping or hitting the structure while under pressure. You can have a depth rating for a vessel, but seals and structure ratings change when bumping the vessel occurs. That's why metal is preferred being it's less prone to change.
Actually not even thought about that the implosion was due to an collision with something, could be, interesting idea.
Pretty cool video overall. Love the David Attenborough AI dub over 😅
Thanks, love David's voice too
Absolutely scummy stealing Sir David Attenborough's voice for a monetized sponsored video.
I bought the licence to use it
@@hnrwagner There's no licenced copy of David Attenborough's voice. I'm guessing you bought a copy of ElevenLabs, which isn't the same thing.
Was not expecting a meme transition to advert. Well done
Thanks, I thought long about how to do it, glad you think it's not mega annoying
I recommend using an audio editing tool to apply a "de-esser" effect to your voice; something about your microphone, environment, or voice causes the s sounds to be very sharp/harsh.
Thanks for the advice
@@hnrwagner you're welcome. I hope it was obvious that this is purely constructive feedback, not a complaint.
Pretty sure this is an AI generated voice of David Attenborough (who does the voice of most national geographic animal shows)
@@hiPokemon1234yep. It’s AI-based DA
These have been getting copyright struck by DA's lawyers
Great job. But the evidence we have seen from the wreck is that the lining between the titanium ending was the failure point.
This is what the French engineers have said. It's also supported by the transcript.
Is that David Attenborough’s voice?
Yes
@@hnrwagneris it not unethical to use someones voice through AI without their permission
@@maplerivers especially to read adverts 😅
A pity, the machine makes an utter meal of rendering DAs voice
@@maplerivers society hasn't decided on that yet.
@@DrTheRich oh sure let me know when Mr Society decides for us
Incredible analysis and simulations. I wonder if the same could be done for Polish TU-154 crash on 10 April 2010 near Smolensk in Russia, with 96 killed.
I have a question: Are the material properties for the used titanium and CFC known? Specifically the "bulk modulus"? Because since I heard about that tragedy I was wondering whether the titanium domes contracted at a different rate than the CFC tube and hence creating shear stress in the dome-tube interface.
Material data are not known only assumptions can be made
What blew me away was seeing a guy apply glue by hand to seal it I mean the sheer stupidity of it is astounding
Very interesting, and rather chilling.
The only consolation to be had is that, for those inside, what happened was so sudden and so devastating, they never knew what hit them.
I ask myself , did they really dont know that something bad is going to happen or did they? If the soul leaves the body, does it think, damn that was unexpected?
@@hnrwagner I choose to believe, the latter. Not so unusual on the face of it, as sudden death for human beings has often taken that basic form. You're minding your own business, then WHAM.
Not something that can be proven scientifically, anyhow.
Wish they could do again with ultra slow mo cameras
This model predicts significant deformation in the end caps. From what little has been shown in the press, the end caps seem to have remained largely the same shape however. Also one would expect the bolts holding the end caps and the interface rings together to be a major structural failure point. Are they even modelled in this simulation?
As shown in the video, the material of the endcaps is not known, it was probably more sturdy than assumed. The bolts cannot be modelled, geometry is not known, material is not known and even if nobody would model them. This model took a week in terms of computation time, if one would consider the bolts, it would probly take weeks or even month
That looks like a very good static load based simulation .. The inertia and accleration of water does not seem to be present. The speed of sound in the composite is much faster than water so as shown the cylinder shatters and then the water accelerates inwards ( generating a powerfull negative going pressure shock wave propergating away from the summarine) but draging the acilillary stuctures inwards with the inrushing water . The weight of hemisphers will slow up the axial inward progress of the water pushing them. However when the now very fast moving water fills the hemispheres there will be a huge positve pressure spike creating an outward moving destructive shock wave, this will blow a lot things outward inculding the window found some waqy from the submarine.
I still hve not seen a convincing simulation that handles the water well .
This simulation takes about a week, with water physics this will probably explode in terms of computation time, also not really sure if it is even possible
@@hnrwagner I worked in the diesel fuel injection world with pressures regularly up to 3000 Bar . Because the smallest injection events are over in less than 0.5 milliseconds everything is shock waves. One further point that has been missed by all commentators is the impractical nature of trying to match the reduction of diameter of a cylinder to an abutting hemisphere as the pressure increases. In steel in both halves we never managed to do it. I predict to the failure started at the glued interface as in the unwanted shear force due to inbalanced deformations pushed the the composite over the edge.
When I saw the hemispherical ends shooting towards each other, I did wonder about the water rushing "in" to fill the space between them and how would that act against the inwards moving ends. My assumption was that the collapse was faster than the water can move.
Would be helpful to hear some simultaneous commentary during the failure simulation on where the failure was assumed to start, how it progressed, etc. It appears to start at the ends of the composite tube, perhaps at the interface with the titanium end rings. Was that because of modulus mismatch between the composite and the titanium? Or did the compressive stress on the composite end surfaces simply exceed allowables? What assumptions were made? How would the model change if, for example, the failure started in the composite tube away from the end rings, perhaps due to cumulative damage from multiple compressive cycles? The graphics are pretty, but in the absence of explanatory detail, it's difficult for viewers to interpret what they're seeing, other than the obvious depiction of a cylinder collapsing axially.
Good point, will do it in a later video
6:26 what is the unit of measurement for time in this? seconds or miliseconds?
Carbon fiber is so hard to model. In my experience failed carbon fiber parts can retain strength in other sections, or in some directions but not the primary direction. Perhaps it failed in a way that kept the hemispheres from rushing in, preventing them from deforming.
Could be, thanks for the advice
So, where did it start?
Did the carbon fiber fail first or the titanium domes or the rings that mate the domes to the tube which are just glued on.
Cfrp cylinder fractured first
does anyone know what aluminum cylinder they used for the inside to lay the fiber on? I was reading alot about airplanes and I read that anodized aluminum experiences sudden huge crack failure after repeated strain, unlike bare aluminum .Thats why some parts are treated with alodine and paint and why you can't just anodize everything on an airplane.
Wouldn't the two hemispheres shoot outward like a rocket rather than be forced inward? Also is it known if bottom weight skid was released or not based on alleged transcript? Weight skid was recovered and don't remember if it had noticeable bend inward as simulated here.
No. Hydrostatic pressure is isotropic, which effectively means all surfaces of the traction acting on the pressure boundary acts inward along the surface normal, even horizontally. For the end caps to shoot outward like your describing, the pressure in the interior chamber would have to somehow rise much higher than the ambient water pressure to expel the caps outward. There is no mechanism here that could cause that. If you are thinking about a jump rocket toy, this only works because the pressure you apply to the chamber by jumping on the bladder becomes much higher than the ambient air pressure acting on the rocket.
@@moonlightcockroach7361 great comment thanks
Stole a certain person's voice.
Mind your own Business
@@hnrwagner Ironic.
@@dannygjkbro why do you care? Hes just probably uncomfortable with everyone on the internet knowing who he is irl incase someone recognises the voice
Sounds like the same narrator for those amazing safety videos made by the Chemical Safety Board (CSB) channel
David Attenborough - it's using his voice for this synthetic narration.
@@Astronetics yes its david
maybe for like 10-15 seconds the ships emergency alarm are making noises. loadcell probably detects that something is bending then boom.
Google Scholar:
scholar.google.de/citations?user=a4sKEKsAAAAJ&hl=en
Researchgate:
www.researchgate.net/profile/Ronald-Wagner
OrcID:
orcid.org/my-orcid?orcid=0000-0003-2749-1455
Timecodes:
0:00 - Introduction
0:16 - What we know and don't know about the TITAN
1:27 - The updated TITAN CAE model and its details
2:12 - The Pathway of Engineering
3:54 - Disclaimer
4:04 - Real-Time Implosion Simulation
4:10 - Implosion Simulation slowed by Factor 10000
4:33 - Simulation of Brittle Composite Cylinder
5:03 - Effect of Implosion on Leg-Support
5:29 - Effect of Implosion on Panels
5:49 - Effect of Implosion on Hemi-Spheres
6:14 - Implosion of TITIAN with different views
7:59 - Logarithmic Strains
why is watching this so weirdly satisfactory?
Its like those pimple poppig videos, you know whats gonna Happen and you watch it anyway
Is the speed of the implosion limited by the speed of sound in the water?
There is for sure some dampening going on but this cannot be included in the simulation so easily
I think number you are interested in is how fast the water comes in which at my best estimate around 180 mph. I don't know exactly because it depends how quckly and what the mass was of the shattering carbon fiber cylinder .
Thye shock wave travels much faster and comunicates the change in circumstances to the surounding water.
The first shock wave propergates AWAY from the vessel at the speed of sound in water at about 1550 m/sec ( 3467 mph) . On one side of the shock wave the water is stationary on the other side all intense pressure due to depth acelerates the water insantly towards the vessel at aprox 180 mph ( depends on the pressure drop accross the shock wave). When all these tons of in rushing water fill the void they have to stop like a hammer hitting an anvil ( any air bubles left will be very small and very very hot) . This causes tremendous pressure spike as the water then rebounds off itself and any solid structure such as the hemisphers creating a new shock wave propergating outwards. This is the really destructive one because one side of the wave the water is rushing inward the other it is rushing outwards this just liquidises things.
I hope this helps you imagine what is going on .
Thank you for this awe inspiring structural simulation…it brought forth both tears of loss and tears of exhilaration by demonstrating that 2 @1/2 spheric End-Caps of sufficient uniform strength separated by a hollow tensile cylinder of insufficient compressive strength will collapse to form a compact sphere when subjected to sufficient external pressure.
Brilliant >> Beer Can Compression 101
Recently I came across a guideline for manned submersibles which stated that you need at least a safety factor of 6 ,the titan had 2.25 from reports, so we now know 2.25 is too low
Once again, Herr Doktor, excellent work. Any chance to re-run with a titanium cylinder as opposed to carbon fiber composite?
Will do
Life extinguished in 0.01 seconds
The AI pronounces Newfoundland wrong. Newfoundland is pronounced New-fin-LAND. I know that's not how its spelled but neither is the way the AI said it "new-fin-LIND".
This better be good.
It is still open for improvements of course but already quite good considering that no one except me seems to bother with this simulation
It looks to me like the cfrp cylinder was the weak point, it appears to collapse in on itself pulling the two titanium hemispheres in towards each other as it collapsed .
On point
Yes, somewhere along the CRFP is assumed to have been the failure point that cascaded.
Did you somehow get David Attenborough to narrate this
Yes :)
What is the v_max of the titanium end-caps?
I took multi-physics in college. This is 1000% legit.
First smart comment this day
Simple scientific description: Squish. Blub. Gone. All in about. 1 second.
Did they found some of the carbon fiber? my guess is the energy of the implosion shredded the fibers into tiny pieces
Have not read anything about it
Most likely no. Your guess is most likely partially correct except my guess would be that the carbon fiber, along with the occupants, were vaporized due to the rapid compression of the air heating the air to many times the temperature of the surface of the sun for a split second.
do the Hindenburg
Interesting idea, not really sure if one can do it but I try
Wow. I know you wish this could be done on gpus...haha....Any thoughts on a 29 meter stainless steel 8 bar pressure tank/ship? ...if you want to get very popular...
not really sure what you mean with "29 meter stainless steel 8 bar pressure tank/ship"?
you mean the ship which impacted into the bridge? thought about doing it but the geometry of the bridge is so complex.
This simulation took 3 days on the university rig, and aborted countless times on the best part due to hourglassing, damn
@@hnrwagner Space ship. The super heavy booster and the ship on top. 5000 tons soda cans.
Would love to do it, but don't know the geometry and material. Do you know where to get those documents?
@@hnrwagner There's a big community around that rocket. Models are already available in stl for 3d printing and 3d visuals etc. let me check..
sound spike/peak at 4:05--headphone users, beware
6:00 shows the rear titanium dome being deformed significantly, though the actual part was recovered almost intact. What gives?
Model is still not good enough after implosion happens, tried different titanium parameters but the calculation time is one week and this is the best I could come up with. Hopefully in a later model I get a better post implosion deformation
I dont understand why they made this submersible out of paper mache, Elmer's glue, aluminim foil, and popsickle sticks. Should have added some JB-Weld.
"No 50-year-old white guys will design our submarine!" (OceanGate company culture)
That is why engineering is mainly (or should be) driven by meritocracy
Fairly close simulation. But you could just watch the real implosion video as filmed from the support remote vehicle.
Can you give a link, would love to watch it
When this happened the guys at work started breaking down what happened and why. This was after a long pause of silence from everyone in the company after hearing the news.
Are your collegues engineers, what did they thought caused it to implode?
@@hnrwagner They are submarine engineers. I could hardly follow with what they where saying when i was around. I still have a hard time following when they start going on about things lol.
No sim required, they existed for a point in time and then they did not in any form
One could say that
Is this David Attenborough?
No
You don't even need to blink to miss it in real time
Yep it is over very quick
oh BOY that was quick. Atleast there was no chance for worrying. yikes.
I saw an article that said they knew they were going to implode 48 - 71 seconds beforehand
no time to cry either ;D
th-cam.com/video/3_Bf05_IJxA/w-d-xo.htmlsi=AbqaMhc6vtLcR49r
David Attenborough's people have been issuing copyright strikes against channels that are using his AI generated voice
Miserable people who have nothing else to do, good that there is no copyright on it
@@hnrwagner Only as long as you don't monetize the videos you should be fine
Where's the loading information? What depth does your model predict failure?
There is none in the video, failure occurs at about 42 MPa if i am not mistaken
@@hnrwagner Wow that means they had about a 10% factor of safety to failure. Completely invalid design. Negligent. Criminal in fact.
@billyd78 nice, yes 11.85% difference to be precise.
Is this your real voice or is this an AI voice?
Is this a Richard Attenborough AI voice simulation?
Yes, pretty scummy using an AI synthesized copy of someone's voice without their consent on a sponsored monetized video.
Yes and no
Hi. As one that is working with one operating ear, the choice of voice is one that is mid-range, distinguishable in pronunciation of consonants and numbers, and overall intelligible in speech.
note: hearing aids are a great invention, but they amplify all sounds including those annoying ones you have not heard in years, so not for me.
Thanks for the input, never even thought about this scenario
Man I feel silly. I thought that the sub emploded, I had no idea it changed colors. Did you happen to catch it's pronouns ?
If only they made the whole thing out of titanium and didn’t cut cost with the plastic crap
are you ripping off David Attenboroughs voice?
yes
@@hnrwagner Why? Why not use your own voice, or just use a proper AI voice where the source voice is paid for, rather than copy an actual presenter's voice with AI?
It explains why the front window blew out.
And because its transparent, it wont probably ever be found
@@hnrwagner yes, good point. Would it fall exactly where it detached, or shoot past it? Or sort of float a bit. Yep, it could be buried in the soft anywhere.
We're now at a point were AI is used to explain experiments, I consider using my phone solely for listening to old music and ditching TH-cam for good.
It's not pure ai, it ai assisted, nothing wrong with it, it's the future , better get used to it
@@hnrwagner the video description doesn't have the necessary disclaimers that content was digitally generated. So reported for misinformation
@@davidaugustofc2574 I am like 100 % sure that you don't know what digital means lol
@@reginawagnerbiolife7867 Well, since I am actually able to read, I can see some videos have Digitally Generated warnings in the description, as TH-cam named them.
The "learn more" would then take me to Disclosing use of altered or synthetic content on Support (dot) Google, where they list their guidelines for AI generated content. Plain and simple.
@@reginawagnerbiolife7867 good for you
The titan 🐍ubmer🐍ible con🐍i🐍ts of many different 🐍tructural element🐍
Its not that bad :p
@@hnrwagner I know I kid 😂😂
It still seems like an invalidating problem that you are simulating shells and not volumes. Why does it do that and how quickly can you change that and pretend this never happened?
With exception of the panels, all is modelled as a volume,so not sure what you are talking about
@@hnrwagner it may be modeled as a volume but when it breaks it's just shells. Shells that go through each other when that shouldn't be possible. Like the rear dome top at 6:07
I don't know what the simulation is doing but it's certainly invalid after it starts breaking.
There's only one way to express this.
Ouch.
No time for ouch, everything just turns black in an instant
It seems to be a multibody simulation more than a multiphysics...
Where do you see multiple bodies
@@hnrwagner In the video multiple parts are shown independently and with different properties. That's a multibody. ¿did you simulate water and air in the outside or inside of the vehicle? Fluid-solid interaction is multiphysics. A compound of solids and a mechanical simulation is not multiphisics.
@@rtorresrtorres it's a structural analysis coupled with heat effects, didn't show the temperature evolution though it is questionable high, will show it later, fluid interaction is too expensive
And that folks is why you don't use Carbon Fibre to make subs!
Although cfrp is good in water for some reasons it has to many disadvantages, would not use it
@@hnrwagnerI am interested to understand the cyclic loading of CFRP. They were able to take it down a few times before it failed. Like you say though its brittle and there is no room for any sort of deformation it just splinters into a million bits.
Were there any human remains found ? Bone fragments , hair .. ?
I have read something about human remains which have been found but no specifics
This what the 787 is made of?
Yes but very thin, that is completly different, cfrp is not meant to be 5 inch thick
🙏🙏
Well said
@@hnrwagner
A whole lot of engineering you did there..🙏
I would love to show how much engineering I did but it's rather boring
Like slapping a mosquito.
More innovations came from that billionaires blunder than the rest of his lifes work combined
Sad but true
I really hope someone didn’t pay to much for this simulation as it was not worth the time. What I mean is that the CEO of this was not worth the time. I feel for those he fooled into getting into that thing. But stupid is as stupid does.
I did the simulation in my spare time at the university for teaching purposes. So the tax payer paid for it
AI voice?
yes
Why is your profile pic a young guy and the voice is of a 78 year old? wtf
The voice is after a couple of cigarettes and beer
@@hnrwagner fair
Ocean gate was a shit company
Second smart comment this day
bros lisp made this shit so unwatchable. fuck this video is shit.
Ok
@@hnrwagner yea thats why its not at higher views, it would be but its unbearable. like actual ear rape.
In the 80's we called this a WAFWOT analysis... What A F'n Waste of Time. Bad input, bad simulation, meaningless output. And now it's posted on YT for pointless speculation. Yay science.
If you say so random Internet Person, you for sure are an expert on this
Who the hell cares? We've already celebrated this vict... Mourned this tragedy.... Stop talking about it. They just rich people.
Dont complain about the rich, become one yourself
Ai voice, low effort, no thanks 10 seconds in
Its one month of work, you have no idea, your loss
That is wrong with you people, just stop, only gloaters are interested RIP.
Ok Mr moral highground
Yeah, how dare we investigate an engineering problem in... depth... we should just declare it the work of Poseidon and sacrifice a goat.