Wtc7 fea

[DC]

It seems some debunkers on JREF still have misunderstood the WTC7 FEA in LS-Dyna.
i hope i can correct that misunderstanding.

for example:

Good catch! And props for the frank admission.

We saw a similar bit of silliness with the WTC 7 collapse graphics in NCSTAR1-9. Those too are greatly exaggerated in scale, so naturally they look quite a bit strange, giving the collapse more of a crushing beer can look than what we saw in reality. Took quite some time for the Truthers to grasp this little detail.

Most FEA's use indeed Displacement scales, so you are able to see the deformations / displacements.
this is mostly needed as the FEA's are used to simulate the part when they are in use under normal loads. so the deformation is very tiny and cannot be seen with your eyes. so the Software does scale those deformations so you can clearly see them.

But there are some FEA's that come without such displacement scalings, because it makes no sence.
for example a total collapse of a building or a crashtest of a car.
in those cases the deformation is so huge you can clearly see them with 1:1 scaling. and other scalings would only confuse.

a total collpase FEA of a building with other scales than 1:1 would mean that while the simulatiopn is only at 50% the animation would already show a total collapsed building. or the other way, while the simulation is already done the animation still shows half a building instead of a totaly collapsed building. that would make no sence at all.

i hope someone can PM this to Mackey, he has me on ignore i think.

 

[Oystein]

It seems some debunkers on JREF still have misunderstood the WTC7 FEA in LS-Dyna.
i hope i can correct that misunderstanding.

for exaple:


Most FEA's use indeed Displacement scales, so you are able to see the deformations / displacements.
this is mostly needed as the FEA's are used to simulate the part when they are in use under normal loads. so the deformation is very tiny and cannot be seen with your eyes. so the Software does scale those deformations so you can clearly see them.

But there are some FEA's that come without such displacement scalings, because it makes no sence.
for example a total collapse of a building or a crashtest of a car.
in those cases the deformation is so huge you can clearly see them with 1:1 scaling. and other scalings would only confuse.

a total collpase FEA of a building with other scales than 1:1 would mean that while the simulatiopn is only at 50% the animation would already show a total collapsed building. or the other way, while the simulation is already done the animation still shows half a building instead of a totaly collapsed building. that would make no sence at all.

i hope someone can PM this to Mackey, he has me on ignore i think.

Are you sure you and R.Mackey are talking about the same animations and graphics?

 

[DC]

yes, WTC 7 collapse graphics in NCSTAR1-9.

 

[T.A.M.]

Most of still have you on ignore, as your transformation to rational being was not well publicized.

TAM

 

[DC]

Most of still have you on ignore, as your transformation to rational being was not well publicized.

TAM

lol,
i should have released a peer-reviewed paper about it

 

[Sword_Of_Truth]

lol,
i should have released a peer-reviewed paper about it

Now you can.

 

[T.A.M.]

lol,
i should have released a peer-reviewed paper about it

I have just released you from the dungeons of my ignore list. Man the company you were keeping down there (a bunch of stinky pdoh socks).

TAM

 

[Quad4_72]

lol,
i should have released a peer-reviewed paper about it

What made you change your mind about 9/11? I have been out of the twoofing game for a while. Last time I checked, you lived in a fantasy world that couldn't be explained through the rational laws of physics as we know them on planet earth.

 

[DC]

What made you change your mind about 9/11? I have been out of the twoofing game for a while. Last time I checked, you lived in a fantasy world that couldn't be explained through the rational laws of physics as we know them on planet earth.

convincing arguments.

but that isnt the topic of this thread.

 

[rwguinn]

Are you sure you and R.Mackey are talking about the same animations and graphics?

I'm only familiar with Ideas, NASTRAN, PATRAN, ANSYS, and ALGOR-but all of them default to Max deflection =10% of screen (or paper size) for viewing. All of them also have a toggle for setting the scale to whatever you want. Scale factor is normally not shown, although some scale (i.e., color code, or maximum deflection) is generally shown.

 

[DC]

I'm only familiar with Ideas, NASTRAN, PATRAN, ANSYS, and ALGOR-but all of them default to Max deflection =10% of screen (or paper size) for viewing. All of them also have a toggle for setting the scale to whatever you want. Scale factor is normally not shown, although some scale (i.e., color code, or maximum deflection) is generally shown.

you do not have to know the FEA programm to know displacement scaling makes no sence in a total collapse FEA.

but as you know Ansys, you maybe also know Ansys LS-Dyna.
or when you have the user manual of LS-Dyna you can read about the NLGEOM seting wich is needed for FEA's with large deflections.
When NLGEOM is on, the default deflection scaling changes to 1:1.

 

[tsig]

deleted already done

 

[ElMondoHummus]

... my ignore list. Man the company you were keeping down there (a bunch of stinky pdoh socks).

TAM

Yeah, isn't that funny? There may be a dozen or so entries on your and my list, but there's really only one or two people on it.

 

[DC]

hehe i rember the time when i was beeing accused of beeing that pdoh guy

 

[DC]

my mail to NIST about this:

Dear Sir or Madam

I have a few questions about the "Global Structural Analysis of the Responce of World Trade Center Building 7 to Fires and Debris Impact Damage".

http://wtc.nist.gov/media/NIST_NCSTAR_1 ... omment.pdf

In particular about the Ansys LS-Dyna FE Analysis.

In Figure 4-18 to 4-35 (Page 80-90) and Figure 4-43 to 4-62 (Page 95-108).

Is there any displacement scaling in those Figures?
I assume that the Ansys setting DMULT was set to 1 (DMULT = 1) in your Analysis, so the displacement was not scaled.
Is this correct?
I also Assume the large-deflection key (NLGEOM) was set ON (NLGEOM=ON) so the large deflection effects was not ignored.
Is this correct?

Did NIST use any deflection scales without mention it and/or mention the deflection scale in the WTC7 Report(s)?

thank you for your answers
with kind regards

Daniel _________
Muttenz, Switzerland

answer from NIST :

Dear Mr. K_____,



Thank you for your inquiry regarding the analysis of the collapse of World Trade Center 7. In answer to your questions regarding displacement scaling, there was no displacement scaling in any of the figures shown for the ANSYS analyses (NCSTAR 1-9, Chapter 11) or the LS-DYNA analyses (NCSTAR 1-9, Chapter 12 and NCSTAR 1-9A). With respect to the large deflection (NLGEOM) this was set to to “ON” so that large deflection effects were captured by the analyses. I hope this answers your questions.



Regards,



Steve Cauffman
Deputy Chief
Materials and Construction Research Division
Building and Fire Research Laboratory
National Institute of Standards and Technology
100 Bureau Drive, Stop 8611
Gaithersburg, MD 20899-8611
Phone: --------*
Fax: --------*
E-mail: stephen.cauffman@nist.gov

my second mail

From: _________
Sent: Wednesday, October 01, 2008 5:11 AM
To: Stephen Cauffman
Subject: Re: Response to question
Importance: High



Dear Mr. Cauffman



I am really sorry to disturb you again. I know you have more important tasks than clearing up laymens confusion.

for me your answer was actually very clear. And i am not a FEA expert.

But for others, that claim to be FEA experts, it seems still not clear at all.



They do belive now that the deflection was normalized, whatever that means.



i quote my debating opponent.



"Having spent 20+ years dealing with people who do not understand a FEA deflection plot, I admit I didn't go directly to the source data. I recognized a normalized plot, and stated it. It is still the case--the deflections are not to scale (that is what "no scale factor was used" means), but are normalized to some max (or min, depending on which absolute is greater), and expressed relative to that. Doesn't matter which model it is."



I would like to clear it up.



I am sure the ANSYS setting DMULT was set to 1, which is the default setting when NLGEOM is set on.



For me that means no displacement scaling.

Will say when ANSYS calculates a deflection of 1 meter, ANSYS will display this as 1 meter deflection, and not as 2 meter deflection (scaling 2:1) nor does it display the deflection as 0.5 meter (scaling 1:2). It will display 1 meter deflection (Scaling 1:1)



Can you confirm me?

or correct me.



thank you very much, and again, sorry to disturb you.



with kind regards

Daniel K____

the second answer from NIST :

Dear Mr. K____,



Thank you for your inquiry. The results of both the ANSYS and LSDYNA analyses had no normalization, amplification, or any other modification in the analyses or plots showing results in the WTC 7 reports.

Perhaps some of the LSDYNA displacement plots are raising these questions. For instance, in the 1A report, figures 3-10 to 3-14 show the vertical and lateral displacements in a true (1:1) scale and the lateral displacements are further indicated with plot colors where any lateral displacements less than or equal to 0.15 m (6 in.) are colored blue to red and any larger lateral displacement was colored red.

I hope this addresses your question.



Regards,



Steve Cauffman
Deputy Chief
Materials and Construction Research Division
Building and Fire Research Laboratory
National Institute of Standards and Technology
100 Bureau Drive, Stop 8611
Gaithersburg, MD 20899-8611
Phone: --------*
Fax: --------*
E-mail: stephen.cauffman@nist.gov

 

[Pardalis]

What made you change your mind about 9/11? I have been out of the twoofing game for a while. Last time I checked, you lived in a fantasy world that couldn't be explained through the rational laws of physics as we know them on planet earth.

He still lives in Fantasy Land, DC is a staunch supporter of Hugo Chávez.

 

[T.A.M.]

He still lives in Fantasy Land, DC is a staunch supporter of Hugo Chávez.

Well he lives in a Font, so what do you expect.

TAM

 

[Seymour Butz]

my mail to NIST about this:
answer from NIST :
my second mail
the second answer from NIST :

This is a good point in the discussion to squash a twoofer point.

Check this again, and follow along:

http://wtc.nist.gov/NCSTAR1/PDF/NCSTAR 1-9A.pdf

Now obviously, Fig 4-63 is "the smoking gun proof" that twoofs say proves that NIST can't get their sims correct cuz reality didn't look anything like this, , so why should we believe them, they're all incompetent, or they're in on it, or scared to speak up, or blah,blah, blah. This Fig is contained in section 4.5. But it's clearly stated that section 4.5 is an analysis of the building without impact damage from WTC1.

Therefore, the rational among us realize that this isn't meant to be a depiction of reality.

The relevant ones are Fig 4-43 to 4-46, taking note of the 2 from the left side, since these are the only views I'm aware of.

 

[DGM]

He still lives in Fantasy Land, DC is a staunch supporter of Hugo Chávez.

You got to admit that there is a marked improvement here (I can't make any definitive judgment because I haven't read any of his posts concerning Hugo Chávez). At least Hugo Chávez is real, that has to account for something.

 

[GlennB]

What made you change your mind about 9/11? I have been out of the twoofing game for a while. Last time I checked, you lived in a fantasy world that couldn't be explained through the rational laws of physics as we know them on planet earth.

convincing arguments.

Bravo