Uncategorized - Vibrationdata Engineering Blog

Launch Vehicle Static Fire Test Explosion Fault Tree

August 6, 2026May 30, 2026 by Tom Irvine

Slide Link Static fire tests are among the most critical — and most dangerous — milestones in a launch vehicle’s life. The vehicle is fully fueled, the engines are lit, and everything that can go wrong is present in one place at one time. This… Read more

Shock, Vibration, Fatigue & Machinery Classes Beginning September 2026

August 26, 2026May 20, 2026 by Tom Irvine

This September 2026 course series provides practical training in shock, vibration, fatigue, structural dynamics, FEA, machinery vibration, acoustics, and rotor dynamics for engineers working with test data, qualification requirements, failure analysis, and mechanical system reliability. Each one-hour class is organized in a semester-style format, with… Read more

Effective Modal Mass and Modal Participation Factors

March 7, 2026February 7, 2026 by Tom Irvine

ModalMass_revK.pdf Effective modal mass and modal participation factors provide a quantitative basis for identifying dynamically significant vibration modes and for guiding modal truncation in structural dynamic analyses. This paper presents a unified formulation for both base-excited systems and grounded systems subjected to externally applied forces.… Read more

Qualification Shock Testing for Launch Vehicle Components, Multiple Flights

November 28, 2025 by admin

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

Tom & Friends’ ebooks

March 2, 2026November 27, 2025 by admin

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

MDOF Frequency Response Function Natural Frequency & Damping Extraction including Modal Frequency Overlap

January 5, 2026August 31, 2025 by admin

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

January 5, 2026August 29, 2025 by admin

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

July 13, 2025 by admin

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

March 9, 2025 by admin

Stress & Fatigue Cumulative Damage Index Response Spectra

February 9, 2025 by admin

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