1. Why did the 47-story tower collapse? It had not suffered from any impact. It had no tilt and no stresses beyond those intended by design. The stresses were, at least, five times less than those causing failure, due to safety factor. Its design took fire into account, and fire insulation on bearing columns was absolutely intact. All high-stress arguments of the Theory do not work here. The honest science must start on studying namely this collapse because in this case we have complete information about the condition of bearing columns and entire structure before the collapse. However, Bazant&Co refuse to do with this problem, and I haven’t seen any reasonable scientific explanation of this collapse in literature. In this case, I can suggest nothing but a man-produced collapse. Or, a sabotage of the company that built the tower. 2. Why was the time of each of three collapses equal to the time of free fall? The fact of free fall time has been noticed throughout the world since the TV translations of the collapses. The Theory explained this fact by small resistance of bearing columns due to tilt and buckling (see the mentioned paper by Bazant&Zhou). My rigorous calculation proved the Theory was wrong because even for zero resistance of bearing columns the time of progressive failure IS much greater than the free fall time (G.P. Cherepanov, Mechanics of the WTC collapse, Int. J. Fracture, 141, p 287-289, 2006). Any progressive failure is a much slower process than free fall. Also, originally I suggested a hypothesis of self-maintaining failure waves that were observed earlier in some brittle materials. However, it appeared to be irrelevant in this case because further exact calculations proved that all collapses started on the floors located significantly lower than the floors hit by terrorists and subjected to fire (G.P.Cherepanov and I.E.Esparragoza, Progressive collapse of towers: the resistance effect, Int. J. Fracture, 143, p 203-206, 2007 ; A hybrid model of WTC collapse, Int. J. Appl. Mech.and Eng., 12(3), p 575-585, 2008). The NIST (Apend.3) computer model of progressive failure would also provide excellent agreement with the observed times of collapses if it would use the correct story (below those hit by terrorists) where the process of failure started. And so, any study of temperature-induced creep of bearing columns became irrelevant to WTC collapse. 3. Why is the Theory speculative? Suppose the doctor tells that a child will live from two to ninety nine years. Would you be happy with such a prediction ? I don’t think so. Meanwhile, this is so far the only kind of prediction the current theory of high-stress-low-temperature creep is practically capable of giving. In my view, there is no reliable, practical theory of this phenomenon, as yet. And so, any talk about high-stress creep is only a talk and nothing more. It is a speculative subject. And Bazant&Co know that. Retelling a proverb I can say: “Wenn Ich CREEP höre, nehme Ich meine pistole!“ I remind some basic facts of the matter. According to NIST studies, only 13% of the total of 287 bearing columns were severed on the critical floor. One can expect about the same share of high-stressed columns subjected to high-stress creep. NIST (Apend.3) established that the towers would have survived if all fire insulation had not be stripped . And NIST concluded that all fire insulation was stripped from all 287 columns before the collapse using the study of column fragments after the collapse. It is a wild assumption. I think it was stripped during the collapse. My own calculation leads to the conclusion that thermal stresses in steel structure were more important than creep, and that dynamic stresses were much less than those in the Theory. The Theory totally ignores thermal stresses which is wrong. However, all these highly-speculative subjects needn’t be studied as much as the clear problems indicated in Sections 1 and 2 above. If one really wants to solve the technical mystery of WTC collapse. Well, it may lie beyond engineering.

© 2010. G.Cherepanov
© 2010. Design, comments. INC-centre.

The story "Scientist's battle" by Genady Cherepanov about the Russian discussion about fracture mechanics and scientific ethics in 1968 (2008, November, Russian text only).

Г. П. Черепанов является основоположником современной механики разрушения, основанной на инвариантном интеграле, носящем его имя. Он известен также своими работами в области прикладной математики, механики и физики твёрдого тела, химической технологии и других областях. Русский учёный, проработавший 30 лет в Советском Союзе и 15 лет – в США, он стал свидетелем и непосредственным участником нескольких крупнейших научных достижений последнего полувека. Один из ста почётных членов Нью-Йоркской Академии Наук и , согласно Американскому Биографическому Институту, один из 500 личностей, оказавших наибольшее влияние в 20-ом веке. Подробная академическая справка о Г.П. Черепанове, список трудов и достижений на его официальном сайте
Так начиналась история механики разрушения в России - "Научные сражения" . (2008, ноябрь)
Литературный очерк о механике разрушения и математике Г.Черепанове за 1979 г. (2009, февраль)
"В энциклопедиях не значится" - Статья Г.Черепанова из газеты "Правда" за 1984 г. (пуб. фев 2010)
Очерк о научных сражениях XXI века от Г.Черепанова (2009, октябрь)

Apendix 2.

Math-Net.ru
Comments

1. Примечание автора 2011 г. В 2011 г. американский журналист Mark H. Gaffney , который обращался ранее ко мне за консультациями по вопросам разрушения ВТЦ, прислал мне большой видео-фильм с изложением мнений различных американских экспертов (в основном из NIST -National Institute for Safety and Transportation - Национальный Институт Безопасности и Транспортирования США) относительно странностей официальной версии. Вы можете сами посмотреть это видео по ссылке (на английском языке) .
   Отмечу два факта из этого фильма, поразивших меня, которые не знал ни я ни большинство американцев.
   1) Все обломки зданий были немедленно отправлены в Китай на переплавку, так что анализ НИСТа обломков----фикция. Всё место преступления было очищено задолго до того времени, когда началась работа НИСТа и комиссии.
   2) Основной владелец всех рухнувших зданий -- миллиардер, еврей (Фамилию и источник Г.Черепанов не указал, ИНК), который заработал на страховке что-то около 10 миллиардов долларов.
   (Г.П.)