Sound-induced Vibration of a Cylindrical Shell

Here is a survey question. NASA-HDBK-7005(2001) gives the Franken method as a semi-empirical method for predicting the vibration response of a cylindrical skin to an acoustic pressure field, via extrapolation. Franken originally published this method in 1962 based on rocket engine static test fire data. There is some anecdotal flight data that the Franken method [...]

Read Full Post »

SpaceX Tour

Some NASA colleagues and I visited SpaceX in Hawthorne, California, on Thursday. Thanks to SpaceX engineers Sam DiMaggio and Jessica Jensen for the guided tour. We saw a Dragon spacecraft being built, as well as several rocket engines. Sam DiMaggio, who leads the loads and environments groups, said they have a policy that no margin [...]

Read Full Post »

Model Correlation

This week I participated in an NESC conference in Los Angeles. One of my colleagues brought up the following point. Finite element models are created to represent physical models for analysis purposes. The finite element model natural frequencies can then be compared to data from a modal test of the actual hardware. At this point, [...]

Read Full Post »

Acoustic Sound Pressure Levels

I recently had a need to compare sound pressure levels (SPLs) on the inside of payload fairings for a number of launch vehicles.  These levels are readily available in online user’s guide for vehicles such as Atlas, Delta, Falcon, Ariane and others. The most critical acoustic environment for satellites & payloads is typically liftoff.   [...]

Read Full Post »

Welcome to Vibrationdata Blog!

Greetings, I will be posting news about my shock & vibration research and latest software and tutorials on this blog. I am currently serving as a industry representative on the NASA Engineering & Safety Center (NESC), Technical Disciplines Team for Loads & Dynamics, under the leadership of Dr. Curtis Larsen.  I am also a scientist at [...]

Read Full Post »