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UAF WTC 7 Evaluation Simulation Plausibility Check (Leroy Hulsey, AE911Truth)
m.youtube.com...
So it looks like the lead researcher and both members of his project team all have Ph.D.'s.
During our nonlinear connection study (Section 2.1.3.2), we discovered that NIST overestimated the rigidity of the outside frame by not modeling its connections, essentially treating the exterior steel framing as thermally fixed, which caused all thermally-induced floor expansion to move away from the exterior. The exterior steel framing was actually flexible, while the stiffest area resistant to thermal movements, i.e., the point of zero thermal movement, was near the elevator shafts.
• Therefore, during our analysis of WTC 7’s response to fire loading (Section 2.6), we found the overall thermal movements at the A2001 base plate support near Column 79 were not sufficient to displace girder A2001 to the point that it walked off its seat (the initiating failure alleged by NIST). Whereas NIST asserted that the differential westward displacement of girder A2001 relative to Column 79 was 5.5 inches and later revised its calculation to 6.25 inches, we found that the westward displacement of girder A2001 3 relative to Column 79 would have been less than 1 inch under the fire conditions reported by NIST.
Under our second approach, we used a solid element model to evaluate the validity of NIST’s collapse initiation hypothesis, introducing a number of assumptions made by NIST that we considered to be invalid or, at best, questionable (Section 3.1). These assumptions included assuming the east exterior wall to be rigid and thermally fixed, assuming shear studs on several beams were broken due to differential thermal movement, assuming no shear studs were installed on girder A2001, and assuming that the bolts fastening girder A2001 to its seats at Columns 44 and 79 were broken (Section 3.1.1). Allowing for these overly generous assumptions, we found the following:
• When girder A2001 is heated to the temperatures assumed by NIST, it expands such that it becomes trapped behind the side plate on the western side of Column 79 as it is pushed to the west by thermally expanding floor beams. This prevents the girder’s web from traveling beyond the bearing seat, thus preventing the girder from walking off its seat (Section 3.2.1).
• NIST, by its own admission, did not include the partial height web stiffeners known to be on girder A2001. In addition to stiffening the web, these stiffeners significantly increase the bending resistance of the flange. In a subsequent analysis where we removed the side plate described in the previous analysis in order to allow for further westward travel of girder A2001, we found that the stresses in the girder flange and stiffener would not be sufficient to cause the flange to fail, thus preventing the girder from walking off its seat (Section 3.2.2).
• In a preliminary collapse initiation hypothesis, NIST posited that beam G3005 buckled because its thermal expansion was restrained by girder A2001. We found that this can happen only when the three lateral support beams S3007, G3007, and K3007 spanning from beam G3005 to the north exterior wall are not included in the model. While these short beams are observed in some of the figures in the NIST report, they are missing from 4 the model(s) used in the thermal and structural analysis shown in the report (Section 3.2.3).
By Mick West
www.metabunk.org/debunked-uaf-study-shows-wtc7-could-not-have-collapsed-from-fire.t9056/
www.metabunk.org...
The study only focuses on one connection. Dr. Hulsey focuses on the connection that NIST identified as a "probable initiation event" in some of its reports, but in fact NIST identified several potential connection failures. This particular connection was not the initiating one in NIST's global collapse models.
The study makes incorrect displacement comparisons. In both 2016 and 2017 Dr. Hulsey made much of a difference in the displacement at column 79 (5.5" west vs. 2" east). But he appears to be comparing the wrong values — global instead of local displacements. www.metabunk.org...
The study makes incorrect temperature related buckling comparisons. Dr. Hulsey claims (slide 82) his study shows col 79 did not buckle due to temperature. He lists this as a point of comparison with NIST. However NIST explicitly makes the exact same observation. www.metabunk.org...
The study does not model fire progression. Dr. Hulsey only used one static temperature distribution, where the actual fires moved around heating unevenly.
The study mischaracterizes NIST's modelling of the exterior. Dr. Hulsey claims the exterior columns were fixed when they were not. www.metabunk.org...
The study mischaracterizes NIST connection modeling in the LS-DYNA model. Dr. Hulsey claims that volumes of the full-building LS-DYNA model did not have connections modeled, but his evidence for this is a misrepresentation of a different model, the ANSYS model. www.metabunk.org...
originally posted by: Gandalf77
Excellent thread--S&F.
Once again, news about WTC7 casts the entire 9/11 story into doubt.
It's difficult to put your head in the sand in the face of scientific analysis like that, but people will still try; confirmation bias has a powerful effect. People just don't want to think about the implications here. We've been programmed by our schools, churches, and the media to not question our government. It's 'unpatriotic' and 'unAmerican' to even remotely suggest we're being lied to.
A good friend of mine is a structural engineer, and I'm going to refer him to this study. He's skeptical about the whole 9/11 truth movement, so I'm very interested to get his professional take on this.
Some Problems with the UAF/Hulsey/AE911Truth WTC7 Draft Report
m.youtube.com...
www.metabunk.org/ae911-truths-wtc7-evaluation-computer-modelling-project.t5627/
www.metabunk.org...
To summarize: Hulsey tries to convince us that the 16-floor ANSYS model of Chapter 11 was modelled with the exterior and the western part made rigid, when in fact NIST had only decided not to model connection failures outside the east floor framing. They did allow the exterior and the western part to respond laterally to what the beams did when heated.
Now on to a big blunder in Hulsey's presentation, which he hasn't corrected since a year ago - and it is a pity that AE911truth as well as other Truther sites actively censored me:
Please turn to page 24:
On the left, he again shows Figure 11–9. Area of the floor where connection failures were modeled, only upside down now. Notice: This is a boundary within the ANSYS model.
On the right, he shows a snapshot from LS-DYNA animation, a model introduced in Chapter 12.
The page is captured with this statement: "Connections were not modeled; outside selected blue space."
That statement is UNTRUE for both the ANSYS and the LS-DYNA model!!
It misconstrues what Figure 11–9 actually shows - "Area of the floor where connection failures were modeled"
More importantly: This distinction simply does not apply to the LS-DYNA model! Hulsey conflates two distinct models!
In other words: Dr. Leroy Hulsey, as of September 06, 2017, has not understood the NIST models!
originally posted by: neutronflux
a reply to: Gandalf77
Are you sure Hulsey has his NIST straight?
originally posted by: neutronflux
a reply to: Gandalf77
West talks more about Hulsey confusing the NIST LS-DYNA and the ANSYS models. West finds it troubling for what’s it worth. Statement starts at 20:20
Some Problems with the UAF/Hulsey/AE911Truth WTC7 Draft Report
m.youtube.com...
The points are further drive home by Oystein
www.metabunk.org/ae911-truths-wtc7-evaluation-computer-modelling-project.t5627/
www.metabunk.org...
To summarize: Hulsey tries to convince us that the 16-floor ANSYS model of Chapter 11 was modelled with the exterior and the western part made rigid, when in fact NIST had only decided not to model connection failures outside the east floor framing. They did allow the exterior and the western part to respond laterally to what the beams did when heated.
Now on to a big blunder in Hulsey's presentation, which he hasn't corrected since a year ago - and it is a pity that AE911truth as well as other Truther sites actively censored me:
Please turn to page 24:
On the left, he again shows Figure 11–9. Area of the floor where connection failures were modeled, only upside down now. Notice: This is a boundary within the ANSYS model.
On the right, he shows a snapshot from LS-DYNA animation, a model introduced in Chapter 12.
The page is captured with this statement: "Connections were not modeled; outside selected blue space."
That statement is UNTRUE for both the ANSYS and the LS-DYNA model!!
It misconstrues what Figure 11–9 actually shows - "Area of the floor where connection failures were modeled"
More importantly: This distinction simply does not apply to the LS-DYNA model! Hulsey conflates two distinct models!
In other words: Dr. Leroy Hulsey, as of September 06, 2017, has not understood the NIST models!