Moderated Continuation - Why a one-way Crush down is not possible

tsig said:
Can't push on a straw?
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You clarified that you thought it hardened until buckling. I don't think a straw is appropriate to the discussion though as it isn't made from a ductile metal and usually has a large slenderness ratio.
 
Tony Szamboti said:
The Requirement in the Appendix was vague also and does not qualify as a discussion of all core beam to column connections.

The NIST report is earily silent for the most part on these connections.

I think we need to stop this discussion between you and I here and save it for the debate.

In fact, I am going to refrain from posting on this forum until after the debate.
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If you're going to carry on with stuff like this -- basic, idiotic mistakes of yours -- in our Hardfire debate, then I'm going to be irritated, and I'm going to rip you a new one on camera.

Please, I beg you, educate yourself. Your showing so far is terrible. Lightyears ahead of Heiwa, yes, but still not ready for prime time.
 
Tony Szamboti said:
You clarified that you thought it hardened until buckling. I don't think a straw is appropriate to the discussion though as it isn't made from a ductile metal and usually has a large slenderness ratio.
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So I-beams don't buckle?
 
bill smith said:
They can disagree all they like. Until they can provide an example or a model the simple fact is that one-tenth of a structure cannot crush the other and stronger nine-tenths of the same structure down to the ground by gravity alone. It has nver been done in the history of this planet and it never will be. Isaac Newton says so. (I can repost Smith's Law if you disagree)
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Yawn. I've lost count, Bill, perhaps you can help out. How many times have I reminded you that the collapsing floors are the BIG PART, that they crush the floors below ONE-AT-A-TIME?


Galileo just spoke with Sir Isaac, who's madder than a wet hen that you took one of his perfectly good laws and grafted idiotic gibberish onto it.

What's that you say? You have to run? Oh, too bad.
 
R.Mackey said:
If you're going to carry on with stuff like this -- basic, idiotic mistakes of yours -- in our Hardfire debate, then I'm going to be irritated, and I'm going to rip you a new one on camera.
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Sweet.....

Although I'm not holding my breath for an mea culpa from Tony - his behavior here indicates that his manners are as poor as his grasp of engineering.
 
bill smith said:
Any structure where the top and lightest 10% crushes the other and stronger 90% down flat on the round by gravity alone will do.

PS....and you better be able to come up with something credible and in the true spirit of the argument. Otherwise WTC1 was demolished without a doubt.
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You've been caught lying again. The collapsing floors will always represent the BIG PART. Why do you continue to lie when we're beating you to a pulp?

Oh, right, that's the reason you continue to lie.
 
Tony,

tfk said:
Tony,
...

My comments were:

1. Why did you use curves for 43A instead of A36 steel? (Since the towers were made with A36.)

2. The correct interpretation of those curves shows the decrease in yield strength, ultimate strength & elastic modulus with rising temp.

3. Bulk modulus cross sectional expansion is irrelevant once the columns go into bending. (Others have shown it to be inconsequential, even if the column stresses stay purely compressive.)

4. Your comment that "As the steel sags ... the inherent strength of the steel will increase" is totally, utterly wrong.

5. Your comment that "the yield strength of steel increases as the degree of distortion increases" is totally wrong.

6. Since the effect that you claim in 5. above is false, it cannot, as you further claim, become more pronounced at elevated temperatures.

7. Your claim that "initial sag in steel cannot be catastrophic..." is wrong.

8. Your claim that "A rising temperature will be needed to offset both the significant increase in yield strength and the slight increase in cross-section area, if collapse is to progress" is completely wrong.

9. You comment that "the upper section should only have moved down slowly and only continued to do so if additional heat was supplied" is both unproven by anything that this paper offers and completely wrong to boot.

___

And now, you AGAIN come back with this reply...



Tony, I don't get it. You're clearly not dumb. You don't strike me as being intentionally, insultingly rude like Heiwa.

Why do you keep suggesting that I've said ANYTHING about energy added after buckling??

Tom

PS. BTW, just to be complete with you, I do believe that you have to add mechanical energy to continue to collapse a beam after it buckles. A small, trivial amount of energy compared to the amount to bring the beam up to the point of buckling.

As described by the correct graph (on the left below).

http://www.internationalskeptics.com/forums/picture.php?albumid=176&pictureid=1437

The energy required is, as indicated on this graph, the area under the Force vs. deflection curve.

And, as shown, FAR from getting stronger, the beam gets much weaker after buckling.

Tom
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Tony Szamboti said:
The paper discusses failure due to compressive rupture, not buckling. Why would you be discussing buckling here? It sounds like you are intentionally distorting what was said in the paper and I really don't want to play your game.

Steel does strain harden once it is yielded and in the plastic region. Additional energy is required to cause additional strain.
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Question 1 is independent of failure mode (compression vs. bending).
Question 2 is independent of failure mode (compression vs. bending).
Question 3 is not independent of failure mode (compression vs. bending).
Question 4 is independent of failure mode (compression vs. bending).
Question 5 is independent of failure mode (compression vs. bending).
Question 6 is independent of failure mode (compression vs. bending).
Question 7 is independent of failure mode (compression vs. bending).
Question 8 is independent of failure mode (compression vs. bending).
Question 9 is mostly independent of failure mode (compression vs. bending).

My question regarding your bringing up energy requirements after yield are unrelated to failure mode.

Most steels (including A36) do strain harden. But strain hardening does NOT increase the yield strength.

With regard to compressive rupture vs. buckling... why on earth would you consider compressive rupture to be the likely failure mode for beams that are thin wall welded box columns that are 1' x 1' x 36' long and not positively constrained from buckling?? In retrospect, don't you think that assumption is really, really tough to justify?

I'm not playing any game here. You've published a paper. You should EXPECT people to challenge you. That is part of the process of being rigorous.

Refusing to answer simple questions & attributing nefarious motives to people who challenge your paper is, in fact, playing a game.

Tom
 
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bill smith said:
Now that we have reversed the burden of proof please feel free to show us your best reasons why WTC1 was not demolished by explosive demolition.
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Gee, I guess the best reason is that a fully-fueled commercial airliner crashed into it at roughly 500 mph, breaking perimeter and core columns and causing extensive fires that weakened the structural steel. Another fairly good reason why WTC 1 and 2 were not brought down by controlled demolition is the total absence of physical evidence for explosives. Reasons 1 and 2 might explain why no demolition professionals think that the collapses of the towers resemble controlled demolitions.

I wonder why you've never heard any of this before today. Why, it's almost as though you can't process information.
 
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bill smith said:
The plane caused limited structural damage leaving more than 85% of the columns between A and C intact. Further it caused a short lived fuel-based fire followed by some fires of office equiment. NIST says these fires burn for on average 20 minutes at a guven location and then move on or go out. Not enough time to seriously affect massive steel columns that were in effect part of a 500-mile heat sink. So the plane's limited effect did not cause the global collapse of WTC1.
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Wow! It's fantastic how you overturned the conclusions of thousands of serious researchers who showed how the fires weakened the structural steel, causing the observed inward bowing of the perimeter columns and the failures of the floor trusses. And to think that you accomplished this Nobel-worthy feat with just stupidity, dishonesty, and near-total ignorance of physics and engineering!

You Go, Girl!
 
bill smith said:
Now that we have reversed the burden of proof please feel free to show us your best reasons why WTC1 was not demolished by explosive demolition.
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Because nobody at WTC heard or saw explosions consistent in intensity or timing with man-made demolition.

And....

In Report From Ground Zero (pgs 310-311), FDNY structures expert Vincent Dunn describes how the WTC towers had effectively no fireproofing when compared to the older steel buildings, built to standards that required 2 inches of brick and masonry on all structural steel. Dunn also says that the WTC towers were unique in the minimal fireproofing and that fire cuased the collapse.

Page 310, Report From Ground Zero
http://snurl.com/j54ud [books_google_com]

Who is Vincent Dunn?
http://unjobs.org/authors/vincent-dunn
​
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Henry Guthard, 70, one of Yamasaki's original partners who also worked as the project manager at the [WTC] site, said, "To hit the building, to disappear, to have pieces come out the other side, it was amazing the building stood. To defend against 5,000 (sic) gallons of ignited fuel in a building of 1350 feet is just not possible."

Report From Ground Zero
http://snurl.com/j54gc (Bottom of page 188)​
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Tony Szamboti said:
For any who are interested the NIST report admits that most of the central core beam to column connections were moment connections.
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Why would an engineer employ such bizarrely unscientific language? The NIST Report is a study--a very large, comprehensive study. It doesn't "admit" anything. What a mad way to express yourself. You don't see how your delusions are affecting your ability to frame your thoughts. The hopeless attempt to make your imaginary conspiracy work has you distorting the way language works. The thousand consultants who worked on the NIST Report are not concealing a secret. That is one of core absurdities of your insane movement.
 
I sometimes think that if the planes had been full of molten steel the life of a debunker would be a lot easier.
 
Newtons Bit said:
Err, looks right to me. The only part where it's wrong is that it only applies to the linear elastic portion of the curve.
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Delta Stress/Delta strain.
It's the SLOPE of the curve...
ETA:
Technically, I suppose you could say that Young's Modulus is the linear slope up to yield.
After yield, the E value you use for additional strain is the delta in the part past yield.
That's why, after yield, very little additional force is required to reach to rupture
 
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rwguinn said:
Delta Stress/Delta strain.
It's the SLOPE of the curve...
ETA:
Technically, I suppose you could say that Young's Modulus is the linear slope up to yield.
After yield, the E value you use for additional strain is the delta in the part past yield.
That's why, after yield, very little additional force is required to reach to rupture
Click to expand...

Oh. He was trying to apply a modulus of 29000ksi post yield. Yea, that's a nono.
 
rwguinn said:
Delta Stress/Delta strain.
It's the SLOPE of the curve...
ETA:
Technically, I suppose you could say that Young's Modulus is the linear slope up to yield.
After yield, the E value you use for additional strain is the delta in the part past yield.
That's why, after yield, very little additional force is required to reach to rupture
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We always referred to the local slope as the Tangent Modulus. Below the elastic limit, the Tangent Modulus = Elastic modulus.

And the curve from the origin to any given point on the curve as the "Secant Modulus". I used the secant modulus for years when designing electronic connectors. Otherwise, you had a bunch of contact performance that you never took advantage of.

Tom
 
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