WTC 9/11 Model Crash Test

The model was built in a scale of 1:500.

[brosephjames]

I dropped a hotwheels car from a scale 100 feet up and it didn't break, clearly i can drive my car off a cliff.

[LadyJay]

You have to build the model the same way the WTC was built. The WTC floors were made of floor trusses and the inner/outer core was made of a lighter steel. Also there should be no columns between the inner & outer steel support cores. Also worth noting that the outer core steel of the WTC was constructed kind of like puzzle pieces (for lack of a better architectural term).

[davidguthrie]

The basic problem with this model is that the steel exterior "skeleton" was stagered 3 story sections, not a 1300 foot piece of steel. They're as strong as the bolts that held them together.

[waltblackadar]

For your next project perhaps you can build an elementary-school model of a volcano, put in the vinegar/baking soda mixture and then claim that there's no such thing as magma.

[uthiriziworldtradecentermi]

it is obvious that it will not be similar because that is, the wtc was built much more differently from those materials apart from the fact that you have to consider that a plane that travels at 900kmph and above that is as wide as the tower causes much more damage

[PapaOystein]

You are correct - it is impossible to build a scale model that would reconstruct a comprehensive reconstruction of the damage pattern.

This is why your model fails, too.

The problem is that you cannot actually do everything to the correct scale, due to the well-know problem that some physical properties scale linearly, some by the square of model scale, some by the cube (and some probably by a mix of those).

For starters: Your model weighs 11.4 kg - to be to scale, mass should be only about 2.4 kg, so your model is too massive by a factor of about 5.
The plane model does have a kinetic energy of about 130 J, while the original flight AA11 had a kinetic energy of about 260 MJ - factor 2 million, or 500x500x8. It's already difficult to say what the KE should be - probably squared scale, as the most interesting properties are a) impacted wall area and b) cross section of columns and spandrels, which both scale with the square of scale.
So you probably have kinetic energy too low by a factor of 8.
Your model in this aspect thus is already off, skewed towards better odds of survival, by a factor of 40. FAIL.

The floors in your model would have a relative strength far in excess what a true scale model would need, as you have homogenous, continuous metal plates, where the original had light-weight concrete floors that would disintegrate entirely upon impact, with open-web trusses, which would fold a lot more.

Finally, to account for the fact that mass scale is 1/500^3, but structural strength/cross-section scales by a factor of 1/500^2, so a difference in scales of factor 500, you'd need to change something else by a factor of 500: Somehow make the column's specific strength lower by a factor of 500, increase gravity by a factor of 500, or perhaps make the plane's impact force higher by a factor 500 (while at the same time not increasing kinetic energy except to correct for your factor 8 error there). This alone appears to be quite impossible.

[spoofman]

You shot a crossbow at a hunk of soldered steel pieces and embellished it 30x over. This is not a simulation of anything.

[kevinhardy]

What is the force, in newtons, holding two metal atoms together? Let’s call that force F. Kinetic energy is E= 1/2mv^2. So the faster and heavier an object is moving, it hits with more energy. But the force F holding atoms together is always the same in the small and large plane. The toy plane has a small amount of kinetic energy pulling at forcce F apart. The Jumbo Jet has millions of times that amount of kinetic energy pulling at that same force F. It’s like pulling 2 magnets apart with a gentle pull vs. With two train engines. Case closed. Study physics 12 my friend. It’s a great course.

[fbportnoy]

Any reasonable human being, with or without a degree in engineering, understands that this comparison is totally flawed.

[Smokr]

Well, for one obvious thing, the perimeter beams you used were solid steel. The perimeter beams in the real towers were hollow beams 14 in wide made out of 1.5 in thick steel plates at the floors where the planes hit. Therefore you should have made a 1:500 model of those hollow beams, which would be .028 in wide (0.7112mm) and made out of .003 in (0.0702mm) thick steel.

Instead, you used solid 1.2mm rods. That works out at 1:500 as 24 in thick solid steel beams - not 14 in hollow steel beams with 1.5 in thick walls.

LUDICROUS!

Just that fact alone completely negates your 'experiment' entirely. I could list five other things that differ considerably, and all of which make your 'model' orders of magnitude stronger than the real towers in scale, but just that first one alone is enough to show how careless and inadequate your 'experiment' is.

[themilkycat]

Too many money and free time for this model, but too little engineering knowledge.

[kristianvitanyi]

Lol, some people think this is accurate. If you drop that plane will it smash to peices like a real one would? If you knock that tower over will it crumble like a real one would? This just isn't how physics works buddy.

[mrfrankiej]

The mesh used to simulate each floor is wrong. The real ones used bar joists. Flimsy lightweight stuff which only joined the outer columns with the inner core. Also the outer columns were made of 3 floor high sections and assembled on top of each other. Like a jigsaw puzzle. The ground level of the model also lacks the tridents which transferred the weight of 3 outer columns into one and ran to the grillages at bedrock.

If this model were constructed like the real towers then im certain the results would significantly vary.

[RyanHeinzman]

Each steel exterior column had a yield & tensile strength that exceeded the aluminum alloy of the 'planes', and the steel while thinner and lighter the higher up, was made of stronger steel, as it ranged from 36k-100k psi strength. The planes going through the buildings like they did is mathematically an improbability, unless some behind the scenes work was done to make it possible. Just for shits and giggles, look up a 500 mph jet vs a small concrete wall.

[agustinhernandez]

La cuestión es que las columnas no eran macizas totalmente, tenían huecos dentro, y era un armazón de piezas, cada columna visible se segmentaba en 110 partes, tal vez más
Los piso eran sostenidos por celosias, no eran tan duras.
Y había un montón de objetos dentro en el evento real que ardían, papeles, cables, electrónicos, etc.
El efecto del fuego no puede ser replicado a exactitud

[troytellsit]

You need to actually construct it the way the WTC was built. You have support columns on the outside as opposed to the inside, and a crossbow is not going to generate enough momentum to even slightly simulate the speed of an aircraft. I would really like to see this tried again but done right next time.

[RTCMAHL]

My guess is you look up and down before you walk across the road.

[joeharrisoncomposer]

Fear often does one of three things to people: 1) Puts us in a position of vulnerability where we seek comfort and assurance, usually in the form of gravitating toward someone who is calm and collected and able to present to us details of what happened and what it means for us, 2) Paralyzes and traumatizes us, and we dissociate and shut down because our brains can't process what just happened, or 3) Puts us in a position of vulnerability where we feel like the only relief will come from developing "theories" and trying to find "patterns, " anything at all that might help us make sense of the source of our fear, because it makes us feel like we have some measure of control over the situation. That third reaction is basically the root of many conspiracy theories, especially ones involving disaster, like JFK, 9/11, COVID-19/QAnon, etc.

At its root, developing or clinging to conspiracy theories is a fear response, possibly even a trauma response. A coping mechanism. And unfortunately our culture primes us for turning to this way of coping with our fear or trauma because we have a cultural stigma against mental illness and seeking psychiatric help, ESPECIALLY men (which is why men are more likely to believe and/or develop conspiracy theories) -- men aren't "supposed" to show emotion, we're not "supposed" to cry, and we're certainly not "supposed" to show fear. All of that is weakness. We're supposed to be IN CONTROL. So conspiracy theories very much play into that.

[klk]

The truss supports is what brought the building down ultimately. But Okay so take the B-52 bomber. It has a fuel minimums where the plane is not allowed to go under a certain percentage because fuel adds structure to the plane/wings. When you have a plane fully loaded with fuel it’s not a weak aluminum tube like it is empty. The fuel turns it into a chunk of iron. Almost like armor piercing steel core. Also the trade center was square tubing columns hollow in the center. But the main point is the towers collapsed exactly how you would expect. A FDNY fire chief was against the buildings because of the design before they were built but port authority had too much power and they shut him up. The truss supports which tied the trusses to the exterior and center columns. The supports were little bitty steel plates that had to hold the entire floor with a 4” concrete slab 50, 000 sqft. As the steel heated up the trusses started sagging then it would collapse and collect. The exterior columns got pulled in if you watch slow mo video. But it failed because the lack of lateral support. Each floor is what provided lateral support. To keep the columns square aka keep the vertical loads going straight down the columns. Once the floors started failing the 3 story column sections started extending to 6-10 story without lateral support so the easy way to demonstrate this is. Take a 2” straw or stick and a 12” straw/stick. Place it vertical on a table and apply vertical pressure with your finger. You will find the 2” straw can take 10x more weight before it Buckles where the 12” straw will bend with 1/4 of the weight. This is what happened. As the floors failed. The columns were growing normally the columns were 3 stories tall. But as a floor would drop it kept extending the lateral support distance. Until the wind and sway was too much for it. This is why the towers had that twist when it’s failed. It was the lateral support that failed.

[seanmcghee]

The plane in the video also wasn't moving at like 500 miles an hour so yeah it wouldn't recreate the damage