Quote (Surfpunk @ Sep 15 2018 02:00pm)

Balrog is Dutch.

Quote (Melatonina @ Sep 15 2018 02:27pm)

Than he has my respect. Amsterdam best eu city

I dont think anyone "debunked" François Roby yet. More links that only 2 billion people in the world can read without google translator :

http://aitia.fr/erd/les-associations-pour-la-verite-sur-le-11-septembre-la-cherchent-elles-vraiment/

Quote (Knoppie @ Sep 15 2018 03:38pm)

That's not specifically thermodynamics, what does the French guy say about the impulse of an aircraft breaking beams ?

Quote (Melatonina @ Sep 15 2018 04:00pm)

I can copy some if anyone wanna try looking for a mistake, I am not a specialist of physic.

"The resistance of materials obeys simple rules: to deform the way of plastic (to be permanent), one needs more elastic stress, and for the rupture, one needs more constraint to the rupture.

A surface is divided by a force. To increase the stress, it is necessary to increase the force and / or to reduce the surface of application.

We can generate a large work force, a greater mass reduction (see the hammer in the conference).
This mass can not be solid: it can be liquid or gaseous. The more the force of the mass limit applicable to the mass slowed down, the interest of the solids for the projectiles.

You find here very beautiful projectile videos against targets (so solid / solid) with very different behaviors depending on the respective hardness:

http://www.youtube.com/watch?v=QfFoMyMoiX4

Some projectiles piercing the target, other than that of the form like pancakes ... When the projectile is like a flower, it can increase its kinetic energy, it is useless. It is lost, the flaps being ejected radially.

The more it is full of materials and in the case of the wing / column interaction it is more complex, on the use of the notion of quadratic moment, but I will not do a course of RoW here ... cons everyone can understand that a sheet of paper can be pierced with a plastic knife, yet plastic is less hard than aluminum.

So your standards stories and projectile polycarbonate that go to ... 7000 m / s (Mach 20 in the air, and still supersonic in the aluminum!), It's a pipe because it has only little to do with the problem.

That said, as I say in the conference, it is not always possible to demonstrate a theory contrary to that of the evidence. This is also the case for "planes" entering the towers ... does anyone find the answer in the NIST reports?"

That post was a reply to that post :

"Hello,
Here is the damage caused by a polycarbonate projectile launched at 7000 m / s on a block of aluminum:
(A new projectile is in the center)
https: //upload.wikimedia.org/wikipe ...
Kinetic energy weapon test.

So yes, aluminum can easily go through steel, everything depends on the mass and speed of the aluminum.
Also note that the aluminum used in the structure and the fuselage of airliners like the 767 is far from the ordinary kitchen alu!
This is the series 7000 (7075, 7050 alkal) alloy having undergone T6 heat treatments giving it a very high mechanical strength, greater than 500 MPa, limited to rupture Rm (MPa) 535 yield strength 470

so well above the cast iron (FGS 500-7 for example) or some structural steels.
With the old standards, structural steels were classified according to their breaking strength symbolized by the letter A followed by the tensile strength expressed in daN / mm 2: example A37. Then they were classified according to their elastic limit symbolized by the letter E followed by the elastic limit expressed in daN / mm2: examples: E24 and E36.

Standard E
Standard A
E24
A37
E36
A52

A37 steel had a tensile strength of 37 daN / mm2, ie 370N / mm2 or 370MPa or 37Kg.
A60 steel had a tensile strength of 60 daN / mm2, ie 600N / mm2 or 600MPa or 60Kg.
https://fr.wikipedia.org/wiki/Acier

https: //fr.wikipedia.org/wiki/Allia ..."

Quote (Knoppie @ Sep 15 2018 04:03pm)

Well apart from the titanium parts in a aircraft, small projectiles are not really comparable to a large mass as an airliner. Beams will break.

Quote (Melatonina @ Sep 15 2018 03:00pm)

I can copy some if anyone wanna try looking for a mistake, I am not a specialist of physic.

"The resistance of materials obeys simple rules: to deform the way of plastic (to be permanent), one needs more elastic stress, and for the rupture, one needs more constraint to the rupture.

A surface is divided by a force. To increase the stress, it is necessary to increase the force and / or to reduce the surface of application.

We can generate a large work force, a greater mass reduction (see the hammer in the conference).
This mass can not be solid: it can be liquid or gaseous. The more the force of the mass limit applicable to the mass slowed down, the interest of the solids for the projectiles.

You find here very beautiful projectile videos against targets (so solid / solid) with very different behaviors depending on the respective hardness:

http://www.youtube.com/watch?v=QfFoMyMoiX4

Some projectiles piercing the target, other than that of the form like pancakes ... When the projectile is like a flower, it can increase its kinetic energy, it is useless. It is lost, the flaps being ejected radially.

The more it is full of materials and in the case of the wing / column interaction it is more complex, on the use of the notion of quadratic moment, but I will not do a course of RoW here ... cons everyone can understand that a sheet of paper can be pierced with a plastic knife, yet plastic is less hard than aluminum.

So your standards stories and projectile polycarbonate that go to ... 7000 m / s (Mach 20 in the air, and still supersonic in the aluminum!), It's a pipe because it has only little to do with the problem.

That said, as I say in the conference, it is not always possible to demonstrate a theory contrary to that of the evidence. This is also the case for "planes" entering the towers ... does anyone find the answer in the NIST reports?"

That post was a reply to that post :

"Hello,
Here is the damage caused by a polycarbonate projectile launched at 7000 m / s on a block of aluminum:
(A new projectile is in the center)
https: //upload.wikimedia.org/wikipe ...
Kinetic energy weapon test.

So yes, aluminum can easily go through steel, everything depends on the mass and speed of the aluminum.
Also note that the aluminum used in the structure and the fuselage of airliners like the 767 is far from the ordinary kitchen alu!
This is the series 7000 (7075, 7050 alkal) alloy having undergone T6 heat treatments giving it a very high mechanical strength, greater than 500 MPa, limited to rupture Rm (MPa) 535 yield strength 470

so well above the cast iron (FGS 500-7 for example) or some structural steels.
With the old standards, structural steels were classified according to their breaking strength symbolized by the letter A followed by the tensile strength expressed in daN / mm 2: example A37. Then they were classified according to their elastic limit symbolized by the letter E followed by the elastic limit expressed in daN / mm2: examples: E24 and E36.

Standard E
Standard A
E24
A37
E36
A52

A37 steel had a tensile strength of 37 daN / mm2, ie 370N / mm2 or 370MPa or 37Kg.
A60 steel had a tensile strength of 60 daN / mm2, ie 600N / mm2 or 600MPa or 60Kg.
https://fr.wikipedia.org/wiki/Acier

https: //fr.wikipedia.org/wiki/Allia ..."

Quote (balrog66 @ Sep 15 2018 04:20pm)

Yeah this isn't even close to proving/disproving anything. It's just speculation based on a random analogy.

If you want me to respond in-depth you're gonna have to post some actual simulation and/or analysis of the disaster. Preferably published in a decent journal.

Some examples:

https://www.cs.purdue.edu/homes/cmh/distribution/PapersChron/WTC_I_Engineering_Perspective.pdf
http://www.us-jpri.org/pdf/en/tsukuba_20150930.pdf
https://cdn.ymaws.com/www.sfpe.org/resource/resmgr/fpe_journal_archives/2009/JFPE_2009_4_1.pdf
https://web.wpi.edu/Pubs/ETD/Available/etd-042907-214619/unrestricted/LaMalva.pdf

Some of these are just MSc or BSc students writing a paper and it's more concise and clear than anything I've seen 9/11 conspiracy theorists ever post.

Quote (Melatonina @ Sep 15 2018 03:28pm)

Simulations won't do better if you treat his work as "speculations" rofl .. I don't even

I am trying to understand the problems that still resist facts, but I'm not going to read all of thoses pdf if you cant give me a resume or something

Quote (Melatonina @ Sep 15 2018 04:11pm)

We can therefore generate stresses with materials whose limit at break is strictly zero, and you balance me comparisons of constraints (which of the rest? In compression? In traction?) As if it was the criterion, proof that you do not even understand the physics of the problem. Where are the quadratic moments of the colliding beams? How is the mass of the flying object relevant? Its effect would be the same (at identical speed) regardless of the impact surface, whether it is 100 cm2 or 100 m2?

We do not do physics by juggling at random with numbers, but understanding the phenomena involved before coming to calculations. My supervisor said to me (a little abruptly): "we never do a calculation before knowing pretty much what it will give".

Quote (balrog66 @ Sep 15 2018 04:32pm)

If you want to somehow prove that the amount of damage caused by that plane crashing into the building is not enough for it to collapse, you can't really do experiments. Which is why simulation is the preferred method.

Pretty much 10/10 simulations are in agreement that the damage caused is definitely enough for collapse to happen.