9/11 Allgemein

tanas schrieb:.... mwahahaha. :D

aber dann bitte nicht wundern, wenn du dich nicht ernst genommen fühlst. ^^

ER_win schrieb:wenn du kein Ingenieur bist, dann verstehst du das eh nicht - such dir einen Physik-Prof. deines Vertrauens und lass dir das Papier erklären. Auf typisch ablenkende "rhetorische" Fragespiele habe ich keinen Bock. Die conclusio der Studie welche Ergebnisse bei "progressiv collaps" und realistischen physikalischen Strukturen nahegelegt werden sollten, steht expressis verbis da.

Niemand zwingt dich das zu glauben...

Taliban: Geistliches Oberhaupt lehnt Auslieferung Bin Ladens ab

Der Uno-Sicherheitsrat hat die radikal-islamischen Taliban in Afghanistan aufgefordert, Osama Bin Laden der amerikanischen Justiz zu überstellen. Die Regierung in Kabul berät unterdessen über eine eventuelle Auslieferung. Das geistliche Oberhaupt sprach sich vehement dagegen aus. Eine Entscheidung wurde allerdings erneut vertagt.

Kompromisslinie: Taliban erwägen Auslieferung Bin Ladens an Drittstaat

Kommt Bewegung in den fest gefahrenen Konflikt zwischen den USA und Afghanistan? Ein hochrangiger Führer hat die Bereitschaft der Taliban erkennen lassen, über die Auslieferung des mutmaßlichen Terroristenführers Osama Bin Laden in ein neutrales Land zu verhandeln.

Taliban lehnen Auslieferung Bin Ladens ab

Afghanistan rechnet mit raschem Gegenschlag der USA - Terroristenführer hat angeblich das Land verlassen

US-Regierung: Auslieferung von Bin Laden reicht nicht

WASHINGTON/ISLAMABAD, 18. September. Eine Auslieferung des mutmaßlichen Terroristenführers Osama Bin Laden reicht den USA offenbar nicht aus, um auf einen Vergeltungsschlag für die Attentate von New York und Washington zu verzichten. "Das Problem ist eindeutig viel größer als Bin Laden", sagte US-Verteidigungsminister Donald Rumsfeld am Dienstag zu Berichten, wonach die Taliban-Führung in Afghanistan Bin Laden unter Umständen ausliefern würde.

Narrenschiffer schrieb:Das ist aber genau der interessante Weg bei der Fragestellung, ob der Angriff auf Afghanistan gerechtfertigt war oder nicht.

Propagating Instabilities

Propagating instabilities feature in structures that are failing progressively. A highly deformed, localised
region —the instability— is driven along the structure from the site of first damage, often at a load
value below the damaging threshold. They are observed, for example, in the plastic collapse of long
pipelines (Kyriakides 1994), where a discrete indentation can spread along the entire length.

...
All columns are assumed to deform axially
and in unison, in a linear one-dimensional way, and the behaviour of a single column is sufficient to
characterise the complete response of a storey:

...
The linear, one-dimensional collapse of an homogeneous multi-storey building is shown schematically

...
Each storey is assumed to compress homogenously such that the overall “wake” above the crush-front
and below the initiation site has a larger, uniform density...

...
Many simplifications have been made in this analysis for the sake of transparency. For example, the
constructional properties of original WTC towers are not homogenous over the entire height, but only
over discrete portions and differently so. The collapse mode is highly idealised: none of the falling mass moves laterally; any impulsive action between successive floor impacts is neglected; and the final stage
of collapse after the crush-front reaches the base is discounted.

Africanus schrieb: Mir scheint, dass Du es selbst nicht erklären kannst, was wenig verwundert, schließlich hast Du zugegeben, dass Du selbst auch kein Ingenieur bist. Nichts auf dem Kasten, aber ein Maul groß wie das eines Nilpferdes, das ist exakt das Bild, das Du von Dir hier vermittelst.

In cases of collisions that involve kinetic energies large enough to cause significant plastic
deformations, it is intuitively expected that these deformations are concentrated in the vicinity
of the impact zone. The model proposed by Bazant and Zhou (2002) is based on this
assumption. However, in the case of a building structure colliding with the ground or another
hard surface, this may not be true. To understand why, a closer look at some distinctive
features of the problem is needed. The structure may be viewed as a body with a high portion
of hollow space colliding with a more or less rigid surface. Most of the mass of this body is
concentrated in the floors – elements oriented parallel to the impact surface and flexible in the
direction of the resulting inertia forces. The columns contain the remaining portion of the
mass. They have high initial stiffness in vertical direction up to the point in time when
significant buckling deformations start to develop.

Thus, the assumption that the falling structure behaves like a rigid body cushioned by
plastically buckling columns in the vicinity of the impact surface is only correct when the
floor deformations are negligible. In fact, as will be demonstrated, the opposite may be the
case: a significant part of the kinetic energy may be dissipated in the floors.

First, a simplified model is developed to gain first insights into the behavior of the structure at
impact and to derive threshold values for various structural properties that have influence on
the ensuing deformation pattern.
...

It is assumed that a sufficient portion of the columns in one story of a steel-framed building is
damaged to trigger a horizontal spread of column buckling across the whole floor area so that
a collision with the ground or the lower structure becomes inevitable.
...

The properties of the impact surface have a significant effect on the magnitude of the impact
forces and their time history. This surface is considered here to be rigid, which seems realistic
in case the structure collides with the ground after the first story is damaged and the
cushioning effect of the forming rubble pile is negligible.
...

The elastic response is neglected and a rigid-perfectly plastic material model is used. It can
easily be shown that the maximum elastic energy that can be stored in the system is only a
small fraction of the kinetic energy in an impact

Balthasar70 schrieb:@ER_win
....ich sehe immer noch nicht das Problem, sie arbeiten mit einen vereinfachten Modell und es wird beschrieben wo vereinfacht wird.

Balthasar70 schrieb:Wo die Zitate die Du hier ins Forum kippst irgendwo auf eine Sprengung hindeuten kann ich auch immer noch nicht erkennen.

Balthasar70 schrieb:....das ist jetzt eine lustige Geschichte, hat aber mit den Modellen zur Berechnung des WTC nichts zu tun.

ER_win schrieb:Ich überlasse es gänzlich deiner Fantasie sowie dem aufgeklärten Hausverstand, wodurch der Einsturz erfolgte, wenn es unmöglich die Gravitation alleine gewesen sein kann.

Balthasar70 schrieb:@ER_win
....warum soll den ein höherer Aufwand betrieben werden um dasoffensichtliche zu beweisen?

Wenn Oma Käthe morgens Tod im Bett liegt wird sie ja auch nicht auf einen Giftanschlag des KGB untersucht.

Stanford Professor Steven Block, an expert on national security and terrorism, spoke with the press Tuesday to answer technical questions surrounding the World Trade Center disaster.

According to his “back–of-an-envelope calculation,” a fully-laden Boeing 767 or 757 jet aircraft would have the impact of approximately one kiloton of TNT when running into the side of a building. That is equal to roughly 1/20th of the energy in the atomic bomb dropped on Hiroshima.

“It’s a staggering amount of energy,” Block said. “The simple calculation shows that any aircraft fully fueled is essentially a giant flying bomb.”

Although the World Trade Center was designed to withstand “amazing kinds of forces” and even an aircraft collision, architects may not have taken into consideration the enormous amount of heat a plane loaded with enough fuel to fly across the country would generate. The intense heat could have melted the buildings’ cores, allowing for the collapses, he suggested.

“You don’t design buildings to withstand nuclear attacks,” he said of the collapse. “Next to an atomic weapon, this is the most [energy] that you can pack in one punch.”
Block, a professor in the Department of Biological Sciences and the Department of Applied Physics, is also a senior fellow at Stanford’s Institute for International Studies. He also consults for JASON, a group of primarily academic scientists that consults for the U.S. government and its agencies on technical matters relating to national security.

The combination of a “kamikaze aircraft on the one hand and a hijacked aircraft on the other” is a totally new terrorist method, he said.

“When you combine the two, you really are talking about a new terror-weapon,” he explained. “We’ve seen that it can be an equipment of great devastation.”