INCOMING!: метеорита в Челябинске, Russian Meteor - February 2013 |
INCOMING!: метеорита в Челябинске, Russian Meteor - February 2013 |
Feb 15 2013, 07:01 AM
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Senior Member Group: Moderator Posts: 3233 Joined: 11-February 04 From: Tucson, AZ Member No.: 23 |
Looks like a small meteoroid decided to spoil 2012 DA14's big day by exploding over Russia...
http://zyalt.livejournal.com/722930.html?nojs=1 -------------------- &@^^!% Jim! I'm a geologist, not a physicist!
The Gish Bar Times - A Blog all about Jupiter's Moon Io |
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Feb 15 2013, 10:31 PM
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
Why are we assuming that 1kPa is the level that would break glass/windows? All of the references I can find put the breaking glass level at around 5-10kPa overpressure but I assume there are other factors that would vary that in a shock wave scenario.
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Feb 15 2013, 10:58 PM
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Member Group: Members Posts: 723 Joined: 13-June 04 Member No.: 82 |
Why are we assuming that 1kPa is the level that would break glass/windows? All of the references I can find put the breaking glass level at around 5-10kPa overpressure but I assume there are other factors that would vary that in a shock wave scenario. I used this paper as a reference: QUOTE Table 1. Typical pressure indicators Typical pressure for glass failure 1 kPa (10 millibar) Minor damage to house structures 4.8 kPa (48 millibar) 50% destruction of brickwork ofhouse 17 kPa (170 millibar) Rupture of oil storage tanks 27 kPa (270 millibar) Severe crushing of cars 34 kPa (340 millibar) Loaded train box cars completely demolished 62 kPa (620 millibar) Probably total destruction of buildings 69 kPa (690 millibar) This discussion has the following overpressures: QUOTE Overpressure* (psig) Expected Damage 0.04 Loud noise (143 db); sonic boom glass failure. 0.15 Typical pressure for glass failure. 0.40 Limited minor structural damage. 0.50-1.0 Windows usually shattered; some window frame damage. 0.70 Minor damage to house structures. 1.0 Partial demolition of houses; made uninhabitable. 1.0-2.0 Corrugated metal panels fail and buckle. Housing wood panels blown in. 1.0-8.0 Range for slight to serious laceration injuries from flying glass and other missiles. 2.0 Partial collapse of walls and roofs of houses. 2.0-3.0 Non-reinforced concrete or cinder block walls shattered. 2.4-12.2 Range for 1-90% eardrum rupture among exposed populations. 2.5 50% destruction of home brickwork. 3.0 Steel frame buildings distorted and pulled away from foundation. 5.0 Wooden utility poles snapped. 5.0-7.0 Nearly complete destruction of houses. 7.0 Loaded train cars overturned. 9.0 Loaded train box cars demolished. 10.0 Probable total building destruction. 14.5-29.0 Range for 1-99% fatalities among exposed populations due to direct blast effects. Since 1 kPa = 0.145 PSI, the kPa equivalents would be: 0.3 kPa Loud noise (143 db); sonic boom glass failure. 1.0 kPa Typical pressure for glass failure. 3.5-7 kPa Windows usually shattered; some window frame damage. Some of the videos clearly show the window frames being heavily damaged and even crushed inward, suggesting an impact at the higher end of the overpressure range, but on the other hand the shock wave must also count as a sonic boom, lowering the needed overpressure by a factor of 3.5 or so. My best guess is that the damage normally expected from a 3.5 kPa overpressure is actually due to a 1 kPa sonic boom overpressure. |
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