APPENDIX — Beam Mechanics (Morphology Discriminator)


Purpose

This appendix states a narrow, audit-scoped claim:

  • Model A’s gold-standard defense relies on one-dimensional crush-down/crush-up style accounting: it is a vertical ledger for energy/momentum transfer.
  • The steel morphology discriminator in Report 5 is not a vertical-ledger question. It is a non-axial moment/torque question: broad smooth curvature and torsion (smooth helical/ribbon curls) distributed over length, rather than hinge-localized kinks/tears/fractures.

Therefore: a 1D vertical ledger does not—and cannot—supply the sustained non-axial loading history required to produce the reported morphology. If Model A cannot specify a concrete non-axial torque pathway with the right collateral signatures, it fails the morphology discriminator under the dossier’s stated boundary assumptions.


What the simulation shows

The beam mechanics simulation is a controlled contrast between two classes of loading histories on an A36-like box member:

  • Hinge-localized loading (impact-like / end-loaded / contact-localized): curvature and twist concentrate into a short zone, producing kinks/local plastic hinges and early fracture behavior in the model.
  • Distributed loading (moment/torque applied over the length): curvature and twist distribute smoothly, producing continuous non-axial curvature and helix-like torsion.

That is exactly the morphology contrast at issue in Report 5: kinked hinge-localized deformation vs smooth distributed curvature + torsion.

So the point is not “is there enough vertical energy?” The point is: localized loading histories do not generate the observed class of smooth distributed morphologies.


Supporting illustration

Beam mechanics simulation: hinge-localized kink vs distributed helix

Repro note: the script that generates this figure is available on request to good-faith reviewers.


What the simulation implies (and what it doesn’t)

  • What it implies: If the reported WTC steel morphologies are accurately described as smooth helical/ribbon curls and distributed torsion, then any adequate Model A explanation must include a distributed non-axial moment/torque pathway (not merely vertical crush-down energy accounting) and must match collateral signatures.
  • What it does not imply: This simulation is not a full building-collapse model, not a proof of a specific source architecture, and not a substitute for metallography. It is a mechanics discriminator: localized vs distributed loading histories produce different morphology classes.


What would neutralize this discriminator (Model A pathway)

This discriminator is neutralized if a Model A pathway can be specified that meets all of the following simultaneously (and is consistent with the recovered morphology record):

  1. Constraint/guide geometry: a concrete, repeatable restraint path that forces a consistent wrap radius and sustained torque history.
  2. Collateral signatures: predicted hinge/tear/kink localization (or other mandatory collaterals) are shown to be absent for good reasons, not by omission.
  3. Thermal history consistency: metallography supports a bulk-soak or gradient history consistent with the invoked thermal mechanism (if thermal warping is claimed).
  4. Axis-of-bending mechanism: a specific contact/loading configuration that supplies the required moment vector in a gravity-dominated environment.

Until then, the dossier treats the morphology as a high-specificity discriminator against purely localized heating/impact narratives.


Where this sits in the dossier