An engineer recently asked me to recommended a vibration test level for his device, which would typically be mounted on a hospital table, including surgical tables. Well… shock would almost certainly be worse than vibration, particularly if the device were somehow accidentally dropped on… Read more
Ring Laser Gyros Acronyms: IMU – inertial measurement unit INS – inertial navigation system RLG – ring laser gyro * * * An INS uses the output from an IMU, and combines the information on acceleration and rotation with initial information about position, velocity and… Read more
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
He that findeth his life shall lose it: and he that loseth his life for my sake shall find it. (See Matthew 10:39) * * * When we are engaged in the service of our fellowmen, not only do our deeds assist them, but we… Read more
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