Frank Greening submits withering critique of new WTC7 drafts

[beachnut]

Do you understand that Dr Greening does not support the "inside job" approach? Have you actually read anything, whether the NIST report or any response?

Truth movement members lack the comprehension to understand the simple facts. This would be way over their heads. JREF posters are able to understand this.
If only the truth movement had functional experts, there would be no truth movement.

 

[DC]

Truth movement members lack the comprehension to understand the simple facts. This would be way over their heads. JREF posters are able to understand this.

yeah , like the nonsence they posted about the deflection scales.....
alot JREF posters overestimate themselfe.

 

[Newtons Bit]

yeah , like the nonsence they posted about the deflection scales.....
alot JREF posters overestimate themselfe.

Are you saying that Risa doesn't have a default deflection magnification of 40?

 

[DC]

Are you saying that Risa doesn't have a default deflection magnification of 40?

did i say that? No

but some other posters in this topic claimed that Greenings is ...... and such because he knows exactly well that the deflection is scaled up.

while most propably it was not scaled at all. because default setting in Ansys for sims with big deflection is no scaling. so if they changed that i would expect NIST to mention it in their report.

some talked like they are the big FE experts while they had no clue about Ansys.......

you also said " This is pretty typical stuff in engineering. " while you did not know the scaling and talked about a diffrent software package.

 

[DC]

I am so damn tired of people who have an axe to grind completely misinterpreting FEM and FEA. Dr Greening is an ___ --he KNOWS better!
Yes--the buildings absolutely DID look like that. All you have to do is scale it. Max deflection of a FEM is nearly always distorted--intentionally. Normal procedure is to set the scale such that max deflection is 10% of the available screen.
This is done so that you can actually SEE the Relative deflections. If you used actual scale (1"=1"), it wouldn't even show.
Dr Greening is using HIS authority as a chemist to denigrate the actual authorities in the field he is so totally clueless in.

my ranting was pointed at such posts......

 

[DC]

Ansys LS-Dyna

Deflection Scaling.

what the Ansys Help tells us :

12.3.1. Controlling Displaced Shape Displays
You can control displaced shape displays in two ways:

By superimposing undisplaced and displaced shapes. A display of a structure's displaced shape will often be more meaningful if you can compare the displaced configuration against the original configuration. You can do this by using the KUND argument on the PLDISP command.

By multiplying displacements for distortion displays. In most small-deformation structural analyses, the displaced shape is hard to distinguish from the undisplaced shape. The program automatically multiplies the displacements in your results display, so that their effect will be more readily apparent. You can adjust this multiplication factor, using the /DSCALE command (Utility Menu> PlotCtrls> Style> Displacement Scaling). The program interprets exactly zero values of this multiplier (DMULT = 0) as the default setting, which causes the displacements to be scaled automatically to a readily discernible value. Thus, to obtain "zero" displacements (that is, an undistorted display) you must set DMULT = OFF.

/DSCALE, WN, DMULT

Sets the displacement multiplier for displacement displays.

GRAPHICS: Scaling

MP ME ST PR PRN <> <> FL EM <> <> PP <>

WN
Window number (or ALL) to which command applies (defaults to 1).

DMULT

AUTO or 0 — Scale displacements automatically so that maximum displacement (vector amplitude) displays as 5 percent of the maximum model length, as measured in the global Cartesian X, Y, or Z directions. This is the default setting when NLGEOM is OFF.

1 — Do not scale displacements (i.e., scale displacements by 1.0, true to geometry). Often used with large deflection results. This is the default setting when NLGEOM is ON.

FACTOR — Scale displacements by numerical value input for FACTOR.

OFF — Remove displacement scaling (i.e., scale displacements by 0.0, no distortion).

USER — Set DMULT to that used for last display (useful when last DMULT value was automatically calculated).



Command Default
The default value is 1.0 when NLGEOM is ON, and AUTO when NLGEOM is OFF.

NLGEOM, Key

Includes large-deflection effects in a static or full transient analysis.

SOLUTION: Nonlinear Options

MP ME ST PR PRN <> <> <> <> <> <> PP <>

Product Restrictions

Key
Large-deflection key:

OFF — Ignores large-deflection effects (that is, a small-deflection analysis is specified). This option is the default.

ON — Includes large-deflection (large rotation) effects or large strain effects, according to the element type.

NLGEOM must have been ON. this means the default seting for DMULT=1.

No deflection scaling.

 

[Newtons Bit]

did i say that? No

but some other posters in this topic claimed that Greenings is ...... and such because he knows exactly well that the deflection is scaled up.

while most propably it was not scaled at all. because default setting in Ansys for sims with big deflection is no scaling. so if they changed that i would expect NIST to mention it in their report.

some talked like they are the big FE experts while they had no clue about Ansys.......

you also said " This is pretty typical stuff in engineering. " while you did not know the scaling and talked about a diffrent software package.

I use FE on a daily basis. I'm working on my own FE program. I think I've used over a dozen different FEA packages. Inlcuding Ansys. Have you ever even used an FEA program much less ANSYS before? I recall them ALL having default deflection amplifcation. Until someone shows a screenshot stating otherwise, I'm going to assume that. I'm not going to trust some truther like you who constantly twists the real-world to meet their own distorted sense of reality.

 

[Newtons Bit]

Deflection Scaling.

what the Ansys Help tells us :







NLGEOM must have been ON. this means the default seting for DMULT=1.

No deflection scaling.

Can you show me in the report where that is so?

 

[DC]

Can you show me in the report where that is so?

this is not from the Report, this is directly from the help files in Ansys Release 11.0 (you want screenshots?)

i only used : Cosmos and Ansys

 

[DC]

I use FE on a daily basis. I'm working on my own FE program. I think I've used over a dozen different FEA packages. Inlcuding Ansys. Have you ever even used an FEA program much less ANSYS before? I recall them ALL having default deflection amplifcation. Until someone shows a screenshot stating otherwise, I'm going to assume that. I'm not going to trust some truther like you who constantly twists the real-world to meet their own distorted sense of reality.

im sure you also have acces to Ansys 11.0. so go read it in the help files.

 

[Newtons Bit]

this is not from the Report, this is directly from the help files in Ansys Release 11.0 (you want screenshots?)

i only used : Cosmos and Ansys

I meant from the WTC7 report that would suggest that they're using that key and not something else.

 

[DC]

I meant from the WTC7 report that would suggest that they're using that key and not something else.

i did not find it in the Report. there are no details about it.

but

Large-deflection key:

OFF — Ignores large-deflection effects (that is, a small-deflection analysis is specified). This option is the default.

ON — Includes large-deflection (large rotation) effects or large strain effects, according to the element type.

i am sure NIST set NLGEOM ON, why would you ignore large deflections in a Total Collapse?

 

[Dave Rogers]

This reminds me of an anecdote by George Mikes to illustrate certain German national tendencies, in which he related the story of two men on a station platform arguing what was the quickest way to travel from Frankfurt to Munich by train, but refusing to look at the timetable because they preferred to reason their cases from first principles. Might it be a good idea for someone to ask NIST what deflection scaling they actually used in the diagram, or would that somehow spoil the fun?

Dave

 

[DC]

This reminds me of an anecdote by George Mikes to illustrate certain German national tendencies, in which he related the story of two men on a station platform arguing what was the quickest way to travel from Frankfurt to Munich by train, but refusing to look at the timetable because they preferred to reason their cases from first principles. Might it be a good idea for someone to ask NIST what deflection scaling they actually used in the diagram, or would that somehow spoil the fun?

Dave

this should not be asked, that HAS to be asked. this belongs in the report.

a FOIA for the Ansys files will be funny

 

[Dave Rogers]

this should not be asked, that HAS to be asked. this belongs in the report.

I have no problem with that. So if, to take a hypothetical example, NIST had put out a draft report for comments, that might be a sensible comment to feed back to them. The point is that you can argue all day long about what software settings you think NIST should have used, but that conveys no information whatsoever about what settings they did use. NIST, on the other hand, should simply be able to tell you. This is equally true of both sides in this argument.

Dave

 

[Newtons Bit]

This reminds me of an anecdote by George Mikes to illustrate certain German national tendencies, in which he related the story of two men on a station platform arguing what was the quickest way to travel from Frankfurt to Munich by train, but refusing to look at the timetable because they preferred to reason their cases from first principles. Might it be a good idea for someone to ask NIST what deflection scaling they actually used in the diagram, or would that somehow spoil the fun?

Dave

It would spoil the fun. I'm inclined to believe Dictator Cheney on the default deflection value is 1 for the large deflection key. I'm just not positive that is what analysis was taking place for that picture or that there's another anaylsis mode they were using that has even more different options.

One could always email NIST, they'd probably tell us.

 

[cmcaulif]

It would spoil the fun. I'm inclined to believe Dictator Cheney on the default deflection value is 1 for the large deflection key. I'm just not positive that is what analysis was taking place for that picture or that there's another anaylsis mode they were using that has even more different options.

One could always email NIST, they'd probably tell us.

Its possible that this option was not specific to the analysis type.

The same option in ADINA applies to almost any analysis type the program runs, and simply lets the program know that it needs to take nonlinearity, p-delta effects and the like into account since it is a large displacement problem. The user can then change the default deflection magnification.

In short, ask NIST.

 

[DC]

I emailed NIST and asked them, i hope i get an answer soon.

 

[e^n]

I emailed NIST and asked them, i hope i get an answer soon.

Have you considered filing a FOIA request for the ANSYS/LS-DYNA models? NIST released the SAP2000 models of the WTC towers so it should be possible to get them.

Unfortunately then you're missing the 6 months it takes to run the LS-DYNA model, but at least you can verify as much as possible.

 

[GregoryUrich]

Dr. Greening has revised and extended his comments

Dr. Greening has revised and extended his comments:

Comments on the Draft Report NIST NCSTAR 1-9: “Structural Fire Response and Probable Collapse Sequence of World Trade Center Building 7”, issued by NIST August 21st, 2008

(Revised and Extended Version of Comments Issued September 11th 2008)

Read it