I have written a function for calculating the natural frequencies and modes shapes of a rectangular plate undergoing in-plane vibration via the finite element method. The function is included in the software posted at in the Matlab GUI package. The function can be accessed via:… Read more
Kinetic & strain energy formulas can be used as a basis for Rayleigh-Ritz or finite element analysis of vibrating structures. Equations for common structures and loading conditions are given in strain_energy.pdf The cases include: Uniform Bar under a Constant Axial Load Bar under a General Axial… Read more
Like Robert Frost, I have miles to go before I sleep, and all because I took the road less traveled… This is a long-term work-in-progress… I am including SEA in my Matlab GUI package. The functions can be accessed via: vibrationdata > Miscellaneous Functions I… Read more
A spacecraft at launch is subjected to a harsh acoustic and vibration environment resulting from the passage of acoustic energy, created during the liftoff of a launch vehicle, through the vehicle’s payload fairing. In order to ensure the mission success of the spacecraft it is… Read more
One of my colleagues asked whether uncertainty margin should be added to the input or the response, particularly for a nonlinear system. I recommend adding to the response. He asked that I write a paper using an acceleration base input which he supplied. The results… Read more
From a colleague… I just wanted to let you know that we would have a GS-13 posting out next week seeking for an experienced strength/fracture engineer to fill a vacant position in my branch here at LSP. I would appreciate very much if you can… Read more
Here is a job opening in Huntsville, Alabama for helicopter air frame finite element analysis: http://www.avnikdefense.com/index.php/careers/current-openings/9-available-positions/37-mid-level-mechanical-engineer-structural-analyst I spoke with the CEO, Michele Kochoff Platt. This is an excellent opportunity. So please forward this link to any of your colleagues who are seeking employment. Note that… Read more
Here are some questions from students that I recently received for shaker table testing of equipment. How are vibration standards developed and how do they relate to the operational environment? Standards may have different purposes. Some of the common ones are: Envelope the actual field… Read more
Here are some papers… Notes on Mechanical Shock & Bending Waves Waves in Structures * * * Functions for calculating wave speeds are given in: Matlab script: Vibrationdata Signal Analysis Package The functions can be accessed via >> vibrationdata > Miscellaneous > Acoustics & Vibroacoustics… Read more
Maximum predicted environment (MPE) levels can be derived for acoustic, shock, and vibration levels where flight data is available. The enveloping for multiple sets of data can be performed using tolerance factors as described in the following papers. Normal Tolerance Factors for Upper Tolerance Limits:… Read more