admin There are several tools for analyzing jet aircraft sound as measured on the ground. The measurements would typically be made for takeoff and final approach at or near an airport. Fly-over sound levels can also be recorded. The tools begin with the unweighted, one-third… Read more
This bridge, near the University of Alabama in Huntsville, was built so that pedestrians and cyclists could safety cross over the road. The support structures on either end have both stairs and gentle ramps. The bridge’s fundamental frequency is 2.2 Hz with 0.16% damping. The… Read more
Launch vehicle and spacecraft equipment must withstand pyrotechnic shock from stage separation and other flight events. Civil engineering structures and equipment must survive seismic events. There are many other examples where military, automotive, telecommunication and other equipment must be designed and tested to meet shock… Read more
Figure 1. El Centro Earthquake 1940, Peak Pseudo Velocity, 36.4 in/sec Launch vehicle and spacecraft equipment must withstand pyrotechnic shock from stage separation and other flight events. Civil engineering structures and equipment must survive seismic events. There are many other examples where military, automotive,… Read more
Here is a loose collection of aviation articles that I have written over the years. Enjoy. aircraft_shock_vibration_acoustics.pdf Tom Irvine
Natural Frequencies of Composite Beams: compbeam.pdf A function for composite beams is included in: Vibrationdata Matlab Signal Analysis Package The function can be accessed via: >> vibrationdata > Miscellaneous Functions I > Structural Dynamics > Beam Bending > General Beam Bending, Composite Laminates Plates &… Read more
An important parameter in random vibration analysis is the peak response, which can be the maximum relative displacement, velocity, acceleration, stress or strain. The peak response can then be compared with the threshold for yielding, ultimate failure, etc. The peak is also important for fatigue… Read more
LV/SC Clampband Release Test Here is an excellent reference on shock testing and analysis: European Cooperation for Space Standardization, Space engineering, Mechanical Shock Design and Verification Handbook, ECSS-E-HB-32-25A, 14 July 2015 download link The Shock Handbook was covered in several presentations at the ESA 2nd Workshop on Spacecraft… Read more
I made a recording of a bird in my backyard in Madison, Alabama. The bird was up in a tall pine tree, and I could not see it. But I was able to identify it from its song with the help of someone on the… Read more
Rocket vehicles mounted on launch stands at Vandenberg AFB, California must be designed and analyzed to withstand potential earthquakes originating on the nearby San Andreas Fault. The vehicles behave as long, slender cantilever beams prior to liftoff. * * * I am going to present… Read more