I am going to present: Extending Steinberg’s Fatigue Analysis of Electronics Equipment to a Full Relative Displacement vs. Cycles Curve at the Dynamic Environments Workshop in El Segundo, California, June 4-6, 2013. I know that travel budgets are very tight, but I hope to meet… Read more
Here is a paper for… Extending Steinberg’s Fatigue Analysis of Electronics Equipment Methodology to a Full Relative Displacement vs. Cycles Curve electronic_rd_n.pdf extending_Steinberg.pptx This paper also shows in a very roundabout way that “fatigue damage equivalence” between sine and random vibration occurs when the sine… Read more
This blog entry is a work-in-progress. Fatigue analysis can be performed in the time domain using rainflow cycle counting. This is an elegant, brute-force approach. One advantage of the time domain approach is that it tends to highlight the occurrences of peaks above 3-sigma for… Read more
Endo & Matsuishi (1968) developed the Rainflow Counting method by relating stress reversal cycles to streams of rainwater flowing down a Pagoda. This method is very useful for fatigue analysis. The rainflow method allows the application of Miner’s rule in order to assess the fatigue… Read more
Matlab is a great programming language and environment because of its ease of use, great visualization, and rapid prototyping abilities. Matlab has a feature called MEX, Matlab Executables. See: Matlab MEX Introduction MEX files allow Matlab scripts to call user-supplied functions written in C/C++ and… Read more
The 2012 Spacecraft and Launch Vehicle Dynamic Environments Workshop will be held in El Segundo, California, June 19-21. The conference information is give at: Workshop Link I will present a paper: An Alternate Damage Potential Method for Enveloping Nonstationary Random vibration I hope to see… Read more
Shock and vibration test specifications for avionics and military equipment have almost always been specified in terms of acceleration. The main reason is that acceleration can easily be measured by accelerometers. Velocity sensors are also available but are less common. Gaberson, Chamblers et al, claim… Read more
Launch vehicle avionics components must be designed and tested to withstand random vibration environments. These environments are often derived from flight accelerometer data of previous vehicles. This data tends to be nonstationary as shown in the figure above. The typical method for post-processing is to… Read more
IEST-RD-DTE012: Handbook for Dynamic Data Acquisition and Analysis The purpose of this Handbook, IEST-RD-DTE012.2, is to provide guidelines for acquiring and analyzing structural (or mechanical) shock and vibration, and acoustic and aerodynamic noise data from flight and ground tests for all categories of aerospace vehicles.… Read more
Some colleagues and I recently debated whether fatigue relationships could be applied to repetitive shock environments. Each of us had a persuasive hypothesis as to whether fatigue was applicable, but none had any data to support his claim. I thus perform my own test at… Read more