Sound Analysis of Plasco Collapse

Perhaps tomorrow I might experiment with snapping some stone tiles in two and seeing what that looks like.

Here a stone tile was suspended between two bricks. A 170lb dynamic weight (me) was applied quickly but gradually. The tile failed with a sharp crack. Analysis shows this was composed of multiple events due to the proximity to the ground.

Setup:
Metabunk 2018-02-06 10-53-56.jpg

First crack:
Metabunk 2018-02-06 10-54-22.jpg

2 frames (about 0.01 seconds) later, first crack noise has decayed:
Metabunk 2018-02-06 10-55-04.jpg

Second crack, plus other noise.
Metabunk 2018-02-06 10-56-30.jpg

Ground impact of wood & tile
Metabunk 2018-02-06 10-57-22.jpg

Sound has decayed:
Metabunk 2018-02-06 10-58-43.jpg

So the initial snap of the tile was over in less than 0.01 seconds, The entire event took less than 0.04 seconds.

It seems entirely reasonable that a rapid serious of large scale crackings would be one possible explanation for the faint rapid series of cracks heard at the onset of the Plasco collapse.


[Minor tech note for completeness, the video was recorded at 240 fps, so each frame is spread somewhere within 0.0042 seconds, with different portions of the frame at different times due to the rolling shutter. So it's impossible to pinpoint an exact time for each frame. However this means, at most, an error of half a frame, or 0.002 second. The waveform and the image sequence still tell the story very well, with the important thing being the initial crack which would be isolated in a larger structure]
 
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Can you cite me where in Colin Hansen's article it talks about the sound waves for impacts of concrete on concrete, steel on concrete, or steel on steel? I can't find the methodology you used to distinguish such sounds from "explosive" noises. All the AE911Truth paper says is "The impulses are each too short in duration to be impact-generated noise." It then cites to page 48 of the Hansen paper. Here is that page in its entirety for ease of reference:

upload_2018-2-2_19-35-47.png

Why do you think anything said on this page rules out impulse or impulse-like sounds the likes of which you have identified in the audio analysis visualization from being created by concrete-on-concrete, concrete-on-steel, or steel-on-steel collisions?

You act like you've made an actual argument, but none of your claims actually follow from the papers you cite or what everyone can easily see in the videos of the collapse.

EDIT: In fact, the audio visualizations you provide in the paper make the "impulses"you've identified look much more like type (b) sound waves based on their visual appearance:
upload_2018-2-2_19-43-24.png

It is largely a waste of time comparing what looks like an anechoic, or time-gated, minimum-phase microphone impulse response (eg. A) with a real-life non-anechoic response from a building. Google things like "reverberation radius" and "RT60"
 
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It is largely a waste of time comparing what looks like an anechoic, or time-gated, minimum-phase microphone impulse response (eg. A) with a real-life non-anechoic response from a building. Google things like "reverberation radius" and "RT60"

Indeed, and what Tony was originally comparing was even more removed from reality than that, an "idealized waveform".

Yesterday someone was shooting a gun a few hundred yards away (I live in the country), so I recorded it. Nothing at all like Plasco, or the idealized wave forms, or the isolated wave forms of the second paper.
Metabunk 2018-02-07 08-46-22.jpg

It's hard to even isolate a gunshot out of it, the entire things is echo/reverberation.
Metabunk 2018-02-07 08-48-48.jpg
(amplitude scaled)
 
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You start with two extremely generalized wave forms presented as idealized examples of an explosive and a punch press, respectively, in a single paper published in 1951.

The Hansen paper linked was published in 2001, not 1951. The ResearchGate date is incorrect. Note it has references in it going up to 1999.

Still irrelevant though.
 
The Hansen paper linked was published in 2001, not 1951. The ResearchGate date is incorrect. Note it has references in it going up to 1999.

Still irrelevant though.

Ah, I relied on the date in the AE911Paper that cited to it. I couldn't figure out exactly where they got that date, but didn't want to spend time trying to sort it out.
 
or some steel rupturing as Mick or benthamitemetric would have us believe.

You wouldn’t say that if you’ve ever been in close proximity of a D-9 ripper shank being snapped off, as I have.

But perhaps a better objective analysis could be done with examining the “Big Blue” crane collapse in Milwaukee. It’s a well known failure from a 12”pin snapping, and it sounds like an explosion .

The failure began with a loud bang as Big Blue's king pin bottom end cap assembly developed radial fractures in its top hat bushing flange
.....
Consequently, a bending moment was imposed on the king pin which it was not designed to resist. A second bang followed four seconds later as additional circumferential fractures developed in the top hat bushing

http://www.heavyliftnews.com/cranes/big-blue-crane-coming-down
Content from External Source

Source: https://youtu.be/ZXr1IeWbP10?t=40
 
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