The punch file method may be used to extract the mass & stiffness matrices from Nastran models. The format is awkward since zero terms are not stored. Also the matrices are assumed to be symmetric, and the upper triangular portion above the diagonal is not… 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
This post is a work-in-progress… Combined Ascent Loads for Launch Vehicle Analysis Equivalent Axial & Line Loads for Launch Vehicles Launch Vehicle and Spacecraft Primary Structure Response to High Frequency Shock and Vibration – Tom Irvine
This is a work-in-progress… The fatigue units are available to students who enroll in the Shock & Vibration course series. __________________________________________________________________ M.H.A. Bonte, A. de Boer, R. Liebregts, Prediction of mechanical fatigue caused by multiple random excitations: stress_psd_1.pdf Dr.-Ing. Marinus Luegmair, Dr.-Ing. Alexander Ziehl, Von Mises… Read more
The top figure is the time history from the El Centro earthquake, North-South horizontal component. The middle is the corresponding Waterfall SRS with 4 second segments and with 50% overlap. The bottom is the spectrogram. The Waterfall SRS is calculated by first taking the complete… Read more
Another work-in-progress… Step 1: Download a video file. Step 2: Play using VLC media player. * * * * * Launch Vehicles Delta 4 Heavy Launch Vehicle Shock Events Pegasus Launch Vehicle Linear Shaped Charge Test * * * * * Helicopters Chinook Ground Resonance… Read more
Equipment must be designed and tested to withstand shock and vibration. Ideally, all equipment would be tested on a shaker table with six-degree-of-freedom control (three translations and three rotations). Such tables and control systems exist but are very expensive. Furthermore, any multi-axis testing requires careful… Read more
Hurt people, hurt people. That’s how pain patterns get passed on, generation after generation after generation. Break the chain today. Meet anger with sympathy, contempt with compassion and cruelty with kindness. Greet grimaces with smiles. Forgive and forget about finding fault. Love is the weapon… Read more
Here is a listing of the webinars and related materials. Matlab script: Vibrationdata Signal Analysis Package 1. Natural Frequencies 2. Sine Vibration 3. Sine Sweep Vibration 4. Random Vibration 5. Fourier transforms 6. Leakage Error, Hanning Window 7. FFTs 8. Waterfall FFT 9. White Noise… Read more