NASA/JPL Component Shock Testing Machine Qualification Shock Test Philosophy for Reusable Launch Vehicle Components by Tom Irvine MPE = Maximum Predicted Environment Proposed Rule: Initial Qualification (one flight): 3 shocks per axis at MPE + 6 dB For each additional flight: 1 shock per axis… Read more
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Tom & Friends’ ebooks
An Introduction to Shock & Vibration Response Spectra Revision H eBook Shock & Vibration Stress & Strain as a Function of Velocity, Revision Q, eBook link Launch Vehicle POGO, Combustion Instability & Thrust Oscillation: Dynamics, Instabilities, and Mitigation Techniques link Airport, Traffic & Community Noise… Read more
Equipment Racks & Earthquakes
Seismic-restrained Isolators The following is an edited response from ChatGPT. Resonant response of the equipment rack circuit boards should not be an issue, because circuit board fundamental frequencies are typically above 200 Hz, whereas seismic energy is mostly below 20 Hz. But electronic components may… Read more
MDOF Frequency Response Function Natural Frequency & Damping Extraction including Modal Frequency Overlap
Here is a revision of what has become an ongoing epic project. I am learning a great deal about modal curve-fitting and using AI. Slides More later… – Tom
Shock, Vibration, Fatigue & Acoustics Classes Beginning January 2026
Each class and each part is one-hour long. The format is similar to a college semester system. Students will receive IACET CEUs. Class Registration Link Basic Shock & Vibration IntroductionVibration TestingExcitation FunctionsSine VibrationSine Sweep VibrationRandom Vibration StatisticsSDOF Response to RandomNon-Gaussian RandomFourier TransformFFTWaterfall FFTSample RateLeakage &… Read more
Tapir Stock Trading Program
Update August, 2, 2025 Last Friday was a downer. But Tapir has these tickers doing well: AZO, URI, MSFT Update ticker list which can be used with the Tapir program: stocks_etf_tickers.txt ________________ Update July 27, 2025 Tapir’s recommendations: SPY, IVV, PH, VOO, GS Matlab code… Read more
Shock, Vibration, Fatigue & Acoustics Classes Beginning June 2025
Each class and each part is one-hour long. The format is similar to a college semester system. Students will receive IACET CEUs. Class Registration Link Basic Shock & Vibration IntroductionVibration TestingExcitation FunctionsSine VibrationSine Sweep VibrationRandom Vibration StatisticsSDOF Response to RandomNon-Gaussian RandomFourier TransformFFTWaterfall FFTSample RateLeakage &… Read more
Stress & Fatigue Cumulative Damage Index Response Spectra
The image is the Stress Response Spectrum of 50 G, 11 msec Terminal Sawtooth Pulse Base Input Presentation: stress_FDS_revC Consider a component which must withstand a dynamic environment and where the stress response is the needed output metric for engineering evaluation. This presentation gives a… Read more
Shock, Vibration & Acoustics Classes Beginning January 2025
Each class and each part is one-hour long. The format is similar to a college semester system. Students will receive IACET CEUs. Class Registration Link Basic Shock & Vibration IntroductionVibration TestingExcitation FunctionsSine VibrationSine Sweep VibrationRandom Vibration StatisticsSDOF Response to RandomNon-Gaussian RandomFourier TransformFFTWaterfall FFTSample RateLeakage &… Read more
Expansion upon ANSYS Random Vibration Fatigue Paper
ANSYS Fatigue Paper Expanding upon ANSYS Fatigue Slides Vibration fatigue calculations are “ballpark” calculations given uncertainties in S-N curves, stress concentration factors, non-linearity, temperature, surface finish, heat treatment, load sequence, multi-axis loading, mean stress, size, geometry and other variables. Perhaps the best that can be… Read more