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PowerPoint Slides: webinar_34_rainflow_fatigue_beam.pptx Audio/Visual File: Rainflow_Cycle_Counting_for_Continuous_Beams.wmv YouTube version * * * References: Steinberg’s Vibration Analysis for Electronic Equipment Rainflow Fatigue Posts * * * Matlab script: Vibrationdata Signal Analysis Package * * * See also: Vibrationdata Webinars Thank you, Tom Irvine

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PowerPoint Slides: Webinar_33_Rainflow_Fatigue.pptx Audio/Visual File: Rainflow_Cycle_Counting.wmv YouTube version * * * References: Steinberg’s Vibration Analysis for Electronic Equipment Rainflow Fatigue Posts * * * Matlab script: Vibrationdata Signal Analysis Package * * * See also: Vibrationdata Webinars Thank you, Tom Irvine

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Rainflow fatigue cycles can be easily calculated for a single-degree-of-freedom subjected to a sine or sine sweep base input.  The reason is that each pair of consecutive positive and negative response peaks forms a half-cycle. The relative fatigue damage can then be calculated from the rainflow cycles. Here are Matlab scripts for performing the rainflow […]

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A number of methods have been derived for performing rainflow cycle counting for a response PSD. Note that they tend to be conservative. The Dirlik method is an example of a semi-empirical method for cycle identification. A Matlab script for performing this method is given at: Dirlik_rainflow.zip * * * The following script calculates the […]

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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 the case of random vibration. These higher peaks can also […]

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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 life of a structure subject to complex loading. The resulting […]

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I will present two tutorials sessions at the Shock & Vibration Symposium. Here are the slides: Shock Response Spectra & Time History Synthesis SAVE_conference_2014_Irvine_shock.pptx Rainflow Cycle Counting for Random Vibration Fatigue Analysis SAVE_conference_2014_Irvine_fatigue_revA.pptx * * * Here is the Matlab GUI multi-function signal analysis package: vibrationdata.zip The main script is: vibrationdata.m The remaining scripts are supporting […]

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PowerPoint Slides: webinar_36_fatigue_nonGaussian_random.pptx * * * References: Rainflow Fatigue Posts Generating Random Time Histories with User-specified Skewness & Kurtosis * * * Matlab script: Vibrationdata Signal Analysis Package * * * See also: Vibrationdata Webinars Thank you, Tom Irvine

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PowerPoint Slides: webinar_35_fatigue_sine_random.pptx Audio/Visual File: Using_Fatigue_to_Compare_Sine_and_Random_Environments.wmv YouTube version * * * References: Steinberg’s Vibration Analysis for Electronic Equipment Rainflow Fatigue Posts * * * Matlab script: Vibrationdata Signal Analysis Package * * * See also: Vibrationdata Webinars Thank you, Tom Irvine

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Here is a paper. Estimating Fatigue Damage from Stress Power Spectral Density Functions: estimate_fatigue_psd.pdf * * * This following Matlab program calculates the cumulative rainflow fatigue damage for an input stress PSD using the following wideband methods: 1. Wirsching & Light 2. Ortiz & Chen 3. Lutes & Larsen, Single-Moment 4. Benasciutti & Tovo, alpha […]

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Aerospace and military components must be designed and tested to withstand shock and vibration environments. Some of this testing occurs as qualification, whereby a sample component is tested to levels much higher than those which it would otherwise encounter in the field. This is done to verify the design. Now consider a launch vehicle component […]

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There is an occasional need to compare the effects of two different power spectral density (PSD) base input functions for a particular component. This would be the case if the component has already been tested to one PSD but now must be subjected to a new PSD specification. A comparison can readily be performed using […]

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