The Problem Here is a problem that comes up more often than the standards would suggest. An engineer is deriving a random vibration maximum predicted environment (MPE) for launch vehicle components mounted very close to the engines. Accelerometer data from engine test stand and stack… Read more
Skyscraper design was once governed almost entirely by strength — could the frame carry gravity, wind and seismic loads with adequate margin? For the new generation of ultra-slender “pencil towers,” the governing requirement has shifted to something more subtle: occupant comfort. A building can be… Read more
The data center construction boom has made a 24/7 mechanical plant into everyone’s new neighbor — and the acoustics run in both directions: noise radiating out to the community, and noise and vibration attacking the equipment inside. Driven by cloud computing and AI, data centers… Read more
By Tom Irvine The spruce soundboard of a concert grand piano and the sheet-steel housing of an industrial gearbox have more in common than their outward appearances suggest. Both are thin panels driven into vibration by an internal source. Both radiate sound into the surrounding… Read more
At John Wayne Airport (SNA) in Orange County, California, noise abatement on departures is managed through a combination of specialized Noise Abatement Departure Procedures (NADPs), strict regulatory limits, and operational constraints. Because SNA is located in a densely populated, noise-sensitive residential area, the airport enforces… Read more
Tapiola Lutheran Church in Espoo, Finland, Opened in 1965 Helmholtz-type resonators are built into the walls of the church. The slots between brick pairs and cavities behind them act as both absorbers and diffusors of sound. The absorption reduces the reverberation time as desired for… Read more
A sound file from the attack on the U.S. Embassy in Cuba has now been made available on the Internet. I did a spectral analysis of this file using my Matlab GUI scripts. The sound source is still unknown. The attacks have caused hearing, cognitive,… Read more
NASA SP-8072 Acoustics Loads Generate by the Propulsion System (Alternate SP-8072 link) The liftoff analysis has been added to the GUI package at: Vibrationdata Matlab GUI The function can be accessed via: >> vibrationdata > Miscellaneous Functions I > Acoustics Vibroacoustics & SEA > acoustics >… Read more
LA Times Article, Supersonic passenger jets might make a comeback, more than a decade after the last Concorde flight link Boom Technology Inc. – Tom Irvine
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