On 6/30/2006 3:28:51 PM, Dan Minette ([EMAIL PROTECTED]) wrote: > > -----Original Message----- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED] > On > > Behalf Of Robert Seeberger > > Sent: Thursday, June 29, 2006 3:20 PM > > To: Killer Bs Discussion > > Subject: Re: Physics Prof Finds Thermate in WTC Physical Samples > > > > Robert G. Seeberger wrote: > > > > > > . A stiffer join means that force is > > > transmitted through the structure more efficiently, so weakening > > > vibrations could have sundered the lower parts of the structure > > > before > > > the actual wave of collapse reached a particular level. > > > > Let me clarify myself a bit here. > > I'm proposing that there is a damaging kinetic shockwave that runs > > ahead of the actual wave of collapse weakening structural members > > to > > the degree that the collapse wave progresses almost unimpeded. > > Ah, that does make sense. If one thinks of the force on a steel > beam when > thousands of tons fall on it, one can think of a significant shock > wave > traveling at the speed of sound. That speed in steel is about 6000 > meters/sec and close to 20,000 feet/sec. >
The question I think is, is this a real effect? As I'm visualizing things, and incorporating the speed of sound info you provide, the vibrational shock runs ahead of the collapse wave by a very great distance (in a structure of this size it would be rebounding throughout the surviving structure during the entire event, essentially hammering every weak link until failure.) bouncing top to bottom with the chaotic vibratory forces being swamped by the resonant vibratory forces that are reinforced with every cycle. The resonant cycles would have an effect that is quite different than the general collapse that evidences mostly lateral shearing forces in that they produce much more longitudinal shear. The only way I can think of to prove such a hypothesis is to sample bolts from the upper building and compare them to bolts sampled from the lower building. The upper building should show evidence of more lateral shear and the lower longitudinal shear. Does this make sense? And am I using the terminology correctly? (I'm not exactly sure about terms used for lateral and longitudinal shear) Of course, this is just intuitive guessing and we all know what value that has.<G> (I'm aware that the kind of resonance I'm speaking of may well be simply a matter of chance peculiar to the specific building and its engineering and not some general rule that could be applied in all such events) xponent Comic Book Logic Maru rob _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
