Severe vibrations likely brought down N. Korean rocket By George Leopold 4/13/2012 3:15 PM EDT WASHINGTON – The failure of North Korea’s three-stage Unha-3 rocket on Thursday (March 12) was most likely caused by severe vibrations at an early point in the flight trajectory known… Read more
As I translate the Book of Mormon into Hebrew, I reuse the translated phrases as they reoccur. The following summarizes the Book of Mormon via a composite of reocurring phrases. The number of occurrences in noted in parentheses……… The Book of Mormon gives Christ’s invitation… Read more
The 2012 Spacecraft and Launch Vehicle Dynamic Environments Workshop will be held in El Segundo, California, June 19-21. The conference information is give at: Workshop Link I will present a paper: An Alternate Damage Potential Method for Enveloping Nonstationary Random vibration I hope to see… Read more
Consider a single-degree-of-freedom (SDOF) system subjected to base excitation. There are certain cases where the response of a system is known, but the base input acceleration is unknown. An example would be a seismic sensor which behaved as an SDOF system. The seismometer data would… Read more
Clintonville, Wisconsin is an inland community, adjacent to Lake Pigeon. USA Today reported on March 21, 2012 that a series of mysterious booms have been fraying residents’ nerves. City administrator Lisa Kuss said the booms have roused people from their beds and into the streets… Read more
I posted a newsletter at: http://www.vibrationdata.com/Newsletters/March2012_NL.pdf The topics are: James Webb Space Telescope Isolation The Prandtl-Glauert Singularity Seneca Guns Loudest Stadium Crowd Please also see my profile at: http://www.nasa.gov/offices/nesc/academy/Tom_Irvine_bio.html Tom Irvine
The Iwate-Miyagi Nairiku earthquake struck northeast Honshu, Japan, on 14 June 2008. This earthquake had a moment magnitude Mw 6.9 according to the USGS. The peak ground acceleration (PGA) had a maximum vector sum (3 component) value of 4278 cm/sec^2 (4.36 G). This is the highest ever recorded… Read more
Shock and vibration test specifications for avionics and military equipment have almost always been specified in terms of acceleration. The main reason is that acceleration can easily be measured by accelerometers. Velocity sensors are also available but are less common. Gaberson, Chamblers et al, claim… Read more
Introduction Neither shock nor vibration response should be used to cover rigid-body acceleration because material limits depend on the strain rate and on the duration of the load. Furthermore, static deflection shapes differ from dynamic mode shapes. Material Stress Limits The following is an excerpt… Read more
The flight accelerometer data was measured on a launch vehicle which shall remain anonymous. This was due to an oscillating thrust vector control (TVC) system during the burn-out of a solid rocket motor. This created a “tail wags dog” effect. The resulting vibration occurred throughout… Read more