WTC Twin Towers - Ozeco41 accepts a Jango Challenge to explain "Initiation"

[ozeco41]

In response to some comments of mine in another thread Jango issued this challenge:

It would be a welcomed occurrence to be casually "walked-through" the technical aspects because as I've said before, my hang up is the initiation sequence, such as, What Had To Fail To Cause The Global Collapse.

I started to explain in line but the OP new thread is more appropriate so let's start the process here:

My Objective - to explain the cascade failure process of WTC1 and WTC2 "initiation stage" up to the point where the Top Block was falling AND ROOSD/Three Mechanisms progression was under way.

I will not be addressing CD claims which means that I must allow for CD options in the mix of contributors to collapse. The understanding of cascade failure is not affected whether or not there was CD. (Think about that before (any of) you ask )

And at least note my "Procedural Ground Rule #1"


My Procedural Ground Rules:
1) It will be my explanation. Not relying on NIST, Bazant or any other authority;
2) My objective for this stage of discussion process will be that you (Jango) comprehend the form of "cascade failure" which initiated the collapses of both Twin Towers;
3) I will leave the possibility of CD in the mix to avoid pre-emptive strikes from either "side";
4) I will start from known facts which should be points of agreement;
5) I will progress in steps - advancing to the next step once we agree on the current step;
6) My process will include explanation of some aspects of engineering which are critical to progress of the cascade failures and which are commonly misunderstood in these discussions;
7) I will be looking for agreement and understanding of the points I make - not vaguely stated or more global counter assertions which are not specifically directed at the points I am making; AND
7) It will be qualitative - not quantitative.

So those are my ground rules - is there anything you (Jango) want clarified?

Step One - Defining and Agreeing the Scenario.

The overall scenario for collapse initiation extends from "aircraft impact" through to "Top Block" falling bodily. The sequence and key points being:
A) Aircraft Impact caused damage and started fires;
B) Damage accumulated as a consequence of fires and any CD which may have been performed;
C) The damage increased to the stage where the "Top Block" started to descend bodily;
D) We may need the intermediary step of "Point at which remaining columns are no longer able to support top block". (Which led immediately to failure of all those columns which has survived to that point.)
E) Top Block descending bodily marks the end of our interest for this topic. (I will take it to the point where "ROOSD" driven progression is under way.)

Do you (Jango) agree those five identify/scope the scenario? Do you (Jango) have any you want to add to define the scenario?

Once we agree those scenario and starting point factors I would go on to explain:
P) The failure is in vertical load carrying - vertical load carrying is the function of columns - failure of columns is therefore the main contributor to collapse initiation - and we have two main reasons for failure viz (i) cutting by impact or CD and (ii) failure in axial overload.
Q) Understanding the balance of factors in failure by axial overload- that is the one place where temperature will be relevant and it is a column by column specific balance of factors. (But we dont need to know the details for every column...we only need generic understanding.)
R) Concepts of "load redistribution" which are central to cascade failure - including why they must be understood in 3D and why load redistribution does not proportionately follow the proportion of already failed columns.

Those will do as starters. Without doubt we will identify more as discussion progresses.

Are you (Jango) comfortable with:
X) The procedural basics - I will be presenting my explanation NOT responding to other person’s ideas of their own explanation; AND
Y) The starting points for the scenario?

Your turn Jango.


PS - add this in somewhere - "As I progress I will identify common misunderstandings which my explanation should help correct. I'll make them anonymous - without fear or favour to which side the errors come from."

PPS Added the (Jango) bits to make my primary focus more obvious in this OPed new thread - my comments in the original thread were a response to Jango so the explicit clarity was not needed. Others who care to join in please recall that Jango is my primary audience and my focus will be on my explanation - not discussion of other people's concepts.

 

[JSanderO]

Interesting... and this thread is only between Ozzie and Jango?

 

[ozeco41]

Interesting... and this thread is only between Ozzie and Jango?

Contributions welcome - obviously I would prefer that they not diverge from the objective of "explain for Jango". To that end I may give little or no attention to any divergent comments.

(But I am a realist/pragmatist. )

 

[LSSBB]

Oz, maybe you should some tieback mechanism to the visual evidence as part of the discussion. Visual is fine. Auditory is a whole 'nother can of something.

 

[ozeco41]

Oz, maybe you should some tieback mechanism to the visual evidence as part of the discussion. Visual is fine. Auditory is a whole 'nother can of something.

Thanks for the comment.

I'm waiting for Jango's response.

However my plan is to lead with my own engineering reasoning to establish broad agreement on what must have happened. Let's call that the "underlying or foundation principles".

AND I want to address a few areas of common misunderstanding of the engineering physics - which naturally means that I will need to provide proper explanations of those aspects.

One example is "load redistribution" where there is often an implied misunderstanding that removal of 25% of columns results in uniform 33.3% extra load on the remaining ones. I will need to explain (a) Reality is that redistribution is dependent on layout geometry of column locations (b) Reality is ALWAYS worse than "proportional even redistribution" AND (c) show why it is.

THEN if at any stage of progress there is a sticking point we could go for evidence - my own preference is for reasoned understanding of the physics. That tells us "why" and gives a tool for future thinking contrast with evidence which says "this happened BUT can you see why?"

AKA I prefer "teacher mode"

 

[NoahFence]

LOL

Still trying to educate the willfully ignorant?

 

[ozeco41]

LOL

Still trying to educate the willfully ignorant?

Most of them are beyond help. But they are free to tag along - if this discussion with Jango goes ahead.

 

[ProBonoShill]

Most of them are beyond help. But they are free to tag along - if this discussion with Jango goes ahead.

I admire your willingness to educate the ignorant over the years and appreciate the patience you have while attempting to do so.

Hopefully you can make Jango see the light but I have my doubts.

 

[ozeco41]

I admire your willingness to educate the ignorant over the years and appreciate the patience you have while attempting to do so.

Explaining and teaching are my main motivations - as the history of my posts will show. I'm not much into "winning arguments".

However my patience is a lot less than it was in the heydays of 2007-8-9.

I was new to the game then and learning myself as I went. My main focus for obvious reasons (civil and military engineer) the engineering applied physics of WTC collapses - mostly Twin Towers because that is where I entered discussion and there is more than sufficient visible evidence to support reasoned explanations of the collapse mechanisms. (And - tho' it is incidental - secondary interest - to me - to show why CD was not needed.)

Hopefully you can make Jango see the light but I have my doubts.

I'd prefer "let" him rather than "make" him.

I'm taking his claimed willingness to learn as genuine at this stage. Will do so until he convinces me otherwise.

The biggest barrier is his difficulty reasoning away from false generalisations and related traps including "if we don't know something it could and probably will change the world we do know".

My first interaction with him some months back on some forum or other - forgotten where - I used the example of CD for the Twins. We know so much that there simply CANNOT be anything hidden from the public which could by itself change the no CD hypothesis. There are dozens (hundreds??) of bits of mutually supporting evidence for "no CD" and the weighted most of them will have to be overturned if someone wants to prove CD. And I don't fall for the "reversed burden of disproof" ploy so beloved of truthers et al.

No Government redacted pages can do that - overturn lots of evidence already in the public domain. (And - for simplicity of explanation - I'm glossing over the fact that the redacted pages complaints are probably more about political actions than technical. The same logic is valid if we change domains from technical >> political. Its just a lot easier to explain by example in the technical arena.)

 

[Jango]

In response to some comments of mine in another thread Jango issued this challenge:
I started to explain in line but the OP new thread is more appropriate so let's start the process here:

My Objective - to explain the cascade failure process of WTC1 and WTC2 "initiation stage" up to the point where the Top Block was falling AND ROOSD/Three Mechanisms progression was under way.

I will not be addressing CD claims which means that I must allow for CD options in the mix of contributors to collapse. The understanding of cascade failure is not affected whether or not there was CD. (Think about that before (any of) you ask )

And at least note my "Procedural Ground Rule #1"


My Procedural Ground Rules:
1) It will be my explanation. Not relying on NIST, Bazant or any other authority;
2) My objective for this stage of discussion process will be that you (Jango) comprehend the form of "cascade failure" which initiated the collapses of both Twin Towers;
3) I will leave the possibility of CD in the mix to avoid pre-emptive strikes from either "side";
4) I will start from known facts which should be points of agreement;
5) I will progress in steps - advancing to the next step once we agree on the current step;
6) My process will include explanation of some aspects of engineering which are critical to progress of the cascade failures and which are commonly misunderstood in these discussions;
7) I will be looking for agreement and understanding of the points I make - not vaguely stated or more global counter assertions which are not specifically directed at the points I am making; AND
7) It will be qualitative - not quantitative.

So those are my ground rules - is there anything you (Jango) want clarified?

Step One - Defining and Agreeing the Scenario.

The overall scenario for collapse initiation extends from "aircraft impact" through to "Top Block" falling bodily. The sequence and key points being:
A) Aircraft Impact caused damage and started fires;
B) Damage accumulated as a consequence of fires and any CD which may have been performed;
C) The damage increased to the stage where the "Top Block" started to descend bodily;
D) We may need the intermediary step of "Point at which remaining columns are no longer able to support top block". (Which led immediately to failure of all those columns which has survived to that point.)
E) Top Block descending bodily marks the end of our interest for this topic. (I will take it to the point where "ROOSD" driven progression is under way.)

Do you (Jango) agree those five identify/scope the scenario? Do you (Jango) have any you want to add to define the scenario?

Once we agree those scenario and starting point factors I would go on to explain:
P) The failure is in vertical load carrying - vertical load carrying is the function of columns - failure of columns is therefore the main contributor to collapse initiation - and we have two main reasons for failure viz (i) cutting by impact or CD and (ii) failure in axial overload.
Q) Understanding the balance of factors in failure by axial overload- that is the one place where temperature will be relevant and it is a column by column specific balance of factors. (But we dont need to know the details for every column...we only need generic understanding.)
R) Concepts of "load redistribution" which are central to cascade failure - including why they must be understood in 3D and why load redistribution does not proportionately follow the proportion of already failed columns.

Those will do as starters. Without doubt we will identify more as discussion progresses.

Are you (Jango) comfortable with:
X) The procedural basics - I will be presenting my explanation NOT responding to other person’s ideas of their own explanation; AND
Y) The starting points for the scenario?

Your turn Jango.


PS - add this in somewhere - "As I progress I will identify common misunderstandings which my explanation should help correct. I'll make them anonymous - without fear or favour to which side the errors come from."

PPS Added the (Jango) bits to make my primary focus more obvious in this OPed new thread - my comments in the original thread were a response to Jango so the explicit clarity was not needed. Others who care to join in please recall that Jango is my primary audience and my focus will be on my explanation - not discussion of other people's concepts.

Roger that, sir, on the Ground Rules.

Comment on the 'Defining and Agreeing the Scenario' section -- in B, you include the option of CD. If you are leaving CD open as an option, CD could therefore possibly predate what constitutes A. Another examination would be that CD coincided with the impacts. Nevertheless, I agree to the concept of initial damage (A), accumulated damage (B), breaking point damage (C), global collapse (D & E).

Just to clarify: how do you want me to respond to you, did you mean through PM or here in this thread?

 

[Jango]

Explaining and teaching are my main motivations - as the history of my posts will show. I'm not much into "winning arguments".

However my patience is a lot less than it was in the heydays of 2007-8-9.

I was new to the game then and learning myself as I went. My main focus for obvious reasons (civil and military engineer) the engineering applied physics of WTC collapses - mostly Twin Towers because that is where I entered discussion and there is more than sufficient visible evidence to support reasoned explanations of the collapse mechanisms. (And - tho' it is incidental - secondary interest - to me - to show why CD was not needed.)


I'd prefer "let" him rather than "make" him.

I'm taking his claimed willingness to learn as genuine at this stage. Will do so until he convinces me otherwise.

The biggest barrier is his difficulty reasoning away from false generalisations and related traps including "if we don't know something it could and probably will change the world we do know".

My first interaction with him some months back on some forum or other - forgotten where - I used the example of CD for the Twins. We know so much that there simply CANNOT be anything hidden from the public which could by itself change the no CD hypothesis. There are dozens (hundreds??) of bits of mutually supporting evidence for "no CD" and the weighted most of them will have to be overturned if someone wants to prove CD. And I don't fall for the "reversed burden of disproof" ploy so beloved of truthers et al.

No Government redacted pages can do that - overturn lots of evidence already in the public domain. (And - for simplicity of explanation - I'm glossing over the fact that the redacted pages complaints are probably more about political actions than technical. The same logic is valid if we change domains from technical >> political. Its just a lot easier to explain by example in the technical arena.)

You have patience?

 

[ozeco41]

Roger that, sir, on the Ground Rules.

Thank you.

Comment on the 'Defining and Agreeing the Scenario' section -- in B, you include the option of CD. If you are leaving CD open as an option, CD could therefore possibly predate what constitutes A. Another examination would be that CD coincided with the impacts.

Your logic is correct. (Well I agree with it which should be near enough the same thing )

My aim/objective for this discussion is that we reach agreed understanding on the mechanism of "cascade failure" as occurred at WTC1 and WTC2 on 9/11. The mechanism is the same whether or not there was CD added in this cascade failure stage.

By leaving CD in the mix I wanted to avoid side tracks - CD committed in the period of cascading failures does not change the mechanism in principle - merely the balance of contributions. My thesis is that sequential failure of columns resulted in the Top Block dropping. The failures resulted from cutting of some columns and axial overload of other columns. Axial overload being the numerically dominant proportion of the failures - tho' even that doesn't make a lot of difference to explanation. All that leaving CD "in the mix" changes is the relative proportion of columns which failed by "cutting" to columns which failed by "squashed to buckling". Doesn't affect understanding of the mechanism overall - only the balance of causes.

You correctly identify the possibility of CD external to my defined scenario. I prefer to take a rain check on that possibility and add it in later if we need to.

Nevertheless, I agree to the concept of initial damage (A), accumulated damage (B), breaking point damage (C), global collapse (D & E).

Thank you - that is what I need for me to press onwards.

Just to clarify: how do you want me to respond to you, did you mean through PM or here in this thread?

Here in thread. We have an audience.

Next two/three stages of explanation will be:
Stage 2 Cascading Failure of Columns.
Establishing sequential column by column failure as the dominating feature of the cascade failures and starting to set the grounds for it being essentially a column by column process - starting to expose some common errors resulting from assumptions of global homogeneity.

(If I drop the "big words" I mean things like (i) assumptions that all the steel had to be heated to failure temperature - a foundation of several of jay howard's current claims - not so - stated overly simply the only column which needs to be heated at any time is the one that will fail next OR (ii) assumptions that failure of a proportion of columns results in proportional redistribution of load to all remaining columns - it doesn't and the real result is always worse.)

Stage 3 Engineering Bits #1 - Load Redistribution.
Some engineering - getting the basics of load redistribution on the table. Easy in principle but quite complicated in full 3D + T(ime) distribution including heat movements - I'll try to avoid going there.

(Stage 4 - Probably "Where does heat fit into this process?")

Give me a few hours.

 

[ozeco41]

You have patience?

Both patience and energy level are a lot less than I had when I first addressed these issues 2007-8-9.

 

[Jango]

Both patience and energy level are a lot less than I had when I first addressed these issues 2007-8-9.

I don't blame you in the least for the amount of years among the stresses of being a married man and IIRC, a father and a grandfather. A lot of guys are like gristle at that point in their life*, so the fact you can be polite and patient with people is a positive.

* = Leave me alone, get out of my chair, quit making so much noise and give me the T.V. remote.

The image that brings forth: https://www.youtube.com/watch?v=xo_QlcSL71s

 

[ozeco41]

I don't blame you in the least for the amount of years among the stresses of being a married man and IIRC, a father and a grandfather. A lot of guys are like gristle at that point in their life*, so the fact you can be polite and patient with people is a positive.

* = Leave me alone, get out of my chair, quit making so much noise and give me the T.V. remote.

The image that brings forth: https://www.youtube.com/watch?v=xo_QlcSL71s

De-facto foster grandfather to about 120-140 kids 5 days per week - driving school buses as a retirement hobby job. Plus I train prospective bus drivers for their "authority" - allows them to carry fare paying passengers.

I enjoy Jeff Dunham's work. (all characters esp Accchhhmed)

BTW - prognosis for relative difficulty of the task before us:
Stage 2 - relatively easy stuff - I hope

BECAUSE
Stage 3 is difficult

Stage 4 should be easier.

 

[ozeco41]

Stage 2 - Ozeco's Explanation of Twin Towers Initiation.
This stage should be relatively easy. Stage 3 will be a challenge for both of us.

Aim of this stage of my explanation: Establish shared understanding - ozeco and Jango - that it was a process of sequential cascading failure of columns which initiated the Twin Towers collapses at the WTC on 9/11.

(Procedural comment: Much of this may be obvious and easily agreed but I want to put down all the necessary steps of logic. I will mark each <<Point for Agreement - which may initially be a point for further explanation. )

For purposes of explanation the Twin Towers 9/11 collapses fall into two stages of collapse mechanism.

The first stage - which I call "initiation" - was a cascading sequential failure of columns in the "impact damage and fire zone" for each Tower.

Initial damage due to the 'plane impact cut some columns and other bits of structure and started fires. The fires caused further progressive damage.

(There may have been some CD activity in this location at this time - see my ground rules.)

Damage accumulated to the stage where the Top Block descended bodily. <<We are already agreed to this point.


The second stage - AKA "progression" falls outside the scope of this explanation. <<Already agreed.

So at the end of the initiation stage all the columns had failed and it was failure of columns which allowed the "Top Block" to "descend bodily".

Other members - floor joists etc - may also have failed BUT the vertical load carrying columns are the ones which, by failing, allowed the Top Block to fall. << Cannot agree this YET - I haven't posted the reasons.

And that is the end point of our discussion - we now need to retrace our steps to work out the why and how.


Outline of Reasoning.
I have asserted - so far without proof - that it was a cascading failure. So what is a cascading failure and why were these two failures cascades?

The essential feature of a cascade failure is that it is a sequence of failures where as each item fails it passes load onto the remaining surviving members. Toppling a row of dominoes probably the simplest and commonest example of a sequence but with no load transfer. You may be aware of electricity grid failures such as the one which affected NE USA and Ontario in 2003. That was also a cascade failure which resulted in sequenced failures due to load transfer. Both of those are simpler in concept than WTC - they are each examples of binary steps - yes/no at each point. WTC 9/11 was several levels more complicated - each step was multi-factor analogue - explanation coming in Stage 3 - but same underlying principles. Sequence and load transfer causing further failures.

The option to a sequenced failure is that all members fail simultaneously - that didn’t happen as shown by the minutes of delays between initial observed motion - settling - tilting then dropping. Damage such as the inward bowing of perimeter being evident some minutes before the end.

So it was a sequence of column failures.

The second part of the proof of it being a cascade is that each failure passes load to other members - the process of redistribution. That should be a "gimme" - there was a fixed amount of weight onto the columns - one column stops holding its weight - something has to hold it.

So there was "load redistribution". We will explore how that works in Stage 3.


Summary of points made:
(i) Failure of columns defines the process; <<Point for Agreement
(ii) During this stage all columns failed; <<Point for Agreement
(iii) allowing the top Block to "fall" (Get lower - descend - it wasn't "free fall" ); <<Point for Agreement
(iv) Three causes of failure - axial overload, cutting by aircraft or CD. <<Point for Agreement

Do you agree those four? Any needing further explanation?

Let's resolve any bits that are unclear - the next stage gets harder.

So - do you agree "that it was a process of sequential cascading failure of columns which initiated the Twin Towers collapses at the WTC on 9/11"?

 

[Jango]

If I am to take the linguistic combination at face value, essentially yeah.

I don't know what's to come in part 3, however, I'd be remiss if I did not inquire about the internal stability and the support structure as a whole (perimeter, core, whatever else is relevant) as time progressed from the initial incident to the last collapse. Since this is your explanation, I'm looking for that insider quip when you see the video footage of the incident and as time progresses. ETA: Similarly, I don't know if such an estimate can be readily provided, but if you were asked to estimate the remaining intact support structures in the time near the plane impacts, what would you theorize to be a realistic representation given the force of the impact and the forces it unleashed inside of the building? Long question, sorry. Furthermore, and I may be mistaken and getting ahead of myself, but a greater intact support structure should require a greater force to bring it down globally in a cascading fashion. 'Should' being the operative word. If CD is on the table as a possibility, CD therefore could = that 'Should'. -- Alternatively, with respect to remnants of the Twin Towers ejecting laterally and vertically as collapse occurred, would that take place under the condition of a fire-induced cascading collapse, a CD cascading collapse, both, more, ?

Nevertheless, I look forward to your next response.

Don't worry about delays, I'm not ignoring or running away. RL stuff, you understand.

 

[ozeco41]

(Hopefully ) some Reassurances about Process - Direction and Progress.
(AKA Do I know where I am heading? ...sure do.)

If I am to take the linguistic combination at face value, essentially yeah.

It's not a task for the faint hearted. It is probably the least understood aspect of WTC Twins collapses at the mid level detail level. Most professionals would simply go for the macro view "It was a cascading failure - so what?" Those planning new buildings would be more interested in how their new building would avoid such a problem. And near certain the decision would not reach the level of structural engineering design. Priority IMO would go to the high level risk management aspects "Should we plan for deliberate terrorist attacks of scale able to collapse the building". And - if something similar does happen again - IMO it will not be just one unaugmented passenger jet .

I don't know what's to come in part 3,

The first chapter of three describing some engineering basics.

however, I'd be remiss if I did not inquire about the internal stability and the support structure as a whole (perimeter, core, whatever else is relevant) as time progressed from the initial incident to the last collapse.

I'm laying foundations for an overall picture.

Your preference for global reasons leading to global answers is showing - this situation is made up of a lot of bits - disparate bits - the elegance of a global explanation DEMANDS that we fit the bits together coherently. And it is the reverse process to your most common approach to reasoning issues.

My objective is that you understand the mechanism. It is multiple factor and 3 Dimensions. Most internet discussion only considers one or two aspects and not in any valid 3D context.

So I am working from the basics and intend to lay out enough of the pieces of the jigsaw puzzle. Part 3 will start to describe one of three types of engineering basics jig saw piece - load redistribution. Then part 4 - factors in how a single column collapses. Part 5 probably Joist Sag pull in and Perimeter Inward bowing.

Those will be enough pieces or building blocks.

The following stages from Part 6 on will start to deal with putting them together. I will probably have to stay with the basics of interactions - the full 3D bit is IMO beyond putting into words on a forum AND being useful for understanding.

And that's the main reason I left CD in the mix. The bits are easy - describing the pieces of jig-saw. The hard bit is joining them into a coherent whole which:
A) Can be understood; AND
B) is accurate enough despite the simplifications.

...the last thing I needed was confusion over CD making life difficult. And even if you disavow CD I am aware that there are others reading.

Since this is your explanation, I'm looking for that insider quip when you see the video footage of the incident and as time progresses. ETA:

You want the full picture explained. I'm assembling the framework of a full picture explanation.

Similarly, I don't know if such an estimate can be readily provided, but if you were asked to estimate the remaining intact support structures in the time near the plane impacts, what would you theorize to be a realistic representation given the force of the impact and the forces it unleashed inside of the building? Long question, sorry.

I think I know what you are asking. I doubt that such "proportional assessments" add anything at this stage where my objective is that you understand the mechanism qualitatively. Lets get the description clear firs THEN add on the how much of each bit quantification if you still need it.

Furthermore, and I may be mistaken and getting ahead of myself, but a greater intact support structure should require a greater force to bring it down globally in a cascading fashion. 'Should' being the operative word.

You seem to be focussed on global unit "A greater force'. cascading is lots of little bits nibbling away the edges. Read that several times - it is one of the main clues to understanding. Don't worry if it is not clear yet - the next three chapters of engineering bits and the following start put them together should start to build the picture. It is "this bit then that bit then this bit then that bit...." - sure - very fast BUT sequential NOT all at once. And not "All this lot" needing a "big force"

If CD is on the table as a possibility, CD therefore could = that 'Should'. -- Alternatively, with respect to remnants of the Twin Towers ejecting laterally and vertically as collapse occurred, would that take place under the condition of a fire-induced cascading collapse, a CD cascading collapse, both, more, ?

All those features are characteristics of a collapsing building - features of the collapse mechanism NOT what started the collapse. That is the central error of truther claims about CD (well one of the central errors) CD is not magic. It is a way of starting or contributing to starting collapses. Just as Aircraft impacts start or contribute to starting collapses. Just as axial overlording starts or contributes to starting collapses.

Nevertheless, I look forward to your next response.

Don't worry about delays, I'm not ignoring or running away. RL stuff, you understand.

Probably best part of a day before I can write Part 3.

 

[Jango]

Roger that.


For me personally, having an estimate/% gives me something to visualize, a point of reference for my mind's eye if you will. It was already known that I was at a disadvantage coming into this, I without hesitation admitted that much both publicly and privately. "Visual aids" are a proven educational technique. I'm not asking for a precise/absolute estimate since one is not available, so I don't view it as a universal/global kind of thing, just a ballpark estimate so I have something to visualize. The level of technicality and mathematics to arrive at a practical estimate is, I will admit once more, beyond my abilities to formulate on my own, which is why you graciously accepted the position to educate me, sir.

Nevertheless, it isn't a deadlocking item for me, as given the enormity of the Towers and the events unfolding, visual aids are in no short demand. Given what you said though, I suspect that I am jumping the gun once more, hence the previous remiss

Your thoroughness is inspiring and I hope the tediousness of the task does not burn you out.

 

[ozeco41]

(Preface to) Stage 3 - Ozeco's Explanation of Twin Towers Initiation.

Roger that.....Your thoroughness is inspiring and I hope the tediousness of the task does not burn you out.

Great and thank you.

You are echoing my own thinking - we need some visuals or training aids:

"Visual aids" are a proven educational technique. I'm not asking for a precise/absolute estimate since one is not available, so I don't view it as a universal/global kind of thing, just a ballpark estimate so I have something to visualize.

How comfortable are you using metaphors or analogies??

Lets try one. I've already said that a cascade failure is not about "one big force" acting on "one big object" (Or words to that effect.) It is more a series of little bits of nibbling at the edges - the little bits adding up to affect the whole. And in the WTC Twin Towers ignition cascade those bits added up in such a rush that it looks like one big effort. Not so - it was an extremely fast series of (relatively) little bits of nibbling at the edges.

So let's try a metaphor - if it is not your scene we can drop it.

Think of an icebreaker ship. It cuts a path through ice floes by nibbling bits of the edge. By shoving its bow up onto the ice floe and breaking bits off the floe. One section at a time. It doesn’t try to do it in one step.

By contrast what would happen if the ice breaker rammed full speed into a solid iceberg? Would the berg split in two? Or would the icebreaker end up with a bloodied nose? (Yeah - OK I mean a dented damaged bow. Loading metaphor on metaphor may not be a good tactic... )

Now the WTC Towers initiation stage of collapse were cascade failures. And a cascade failure is little by little - step by step - NOT "all at once in one big bang".

Sure those cascade failures were very fast - seconds only overall for the main failure part of the process - which was probably hundreds of distinct steps. BUT fast or not the mechanism was very definitely a sequence of steps. Each one dependent on the one before it to give it a "kick off". as the icebreaker breaks each bit off the edge of the floe it clears its path to get at the next bit, Then the next...then the next.

Change the metaphor - picture a row of dominoes set up to topple in sequence - push the first one and the second falls then the third then the.....

The WTC cascade failures - thousands of times larger scale than a row of dominoes, orders of greater complexity still ran at about the speed of a row of dominoes. If anything faster.

OK Pause there - do those metaphoric analogies help or hinder? If they help -- great we can use them. If not I will obviously need to use different "training aids".

The point I am trying to get across is that a cascade failure is not one big step, one big force, one big bang. It is a sequence of relatively little steps/forces/bangs.

Can you think of it as a lot of relatively little steps in rapid sequence?