Here is an excerpt from a National Transportation Safety Board Aircraft Accident Report… Research has shown that fundamental frequency (pitch) can convey information about a speaker’s psychological stress. With regard to fundamental frequency, the Safety Board used the following guidelines from two previous accident investigations… Read more
I have written some tutorials on avionics component isolation which may be downloaded at: avionics_iso.pdf six_dof_isolated.pdf * * * The Matlab GUI scripts are given in the GUI package at: Vibrationdata Matlab GUI Package The function is accessed via: Miscellaneous > Structural Dynamics > Spring-Mass… Read more
The plate is aluminum, 0.063 inch thick. The fixed edge length is 6 inch. The free edge length is 4 inch. The vibration mode was calculated via the Rayleigh method using an assumed displacement function, as carried out via Matlab script: fixed_free_fixed_free_plate.m The method is… Read more
I have posted a Vibrationdata Newsletter with an aviation theme at: http://www.vibrationdata.com/Newsletters/August2011_NL.pdf The articles include discussions of . . . 1. The XF-84H turboprop aircraft which had supersonic blade tip velocity 2. Aircraft landing shock 3. Turbofan engine buzz-saw noise Military Aircraft Carrier & Normal… 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
Dr. Curtis Larsen asked me to distribute this newly-published “Lessons Learned” document. It is oriented to systems engineering. NASA/CR—2011–216468, Lessons Learned in Engineering J.C. Blair, R.S. Ryan, and L.A. Schutzenhofer Al Signal Research, Inc., Huntsville, Alabama Download Link Topics of interest include: turbopump vibration &… 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
With the encouragement of my NASA colleagues, I have started a Python Blog at: Vibrationdata Python Blog Please visit this site and contribute your own experience. Thank you, Tom Irvine
FreeMat is an open-source software environment similar to Matlab. The latest version is 4.0, released 2009-10-09. I tried FreeMat with one of my Matlab scripts which prompts the user for keyboard input. Unfortunately, this resulted in an error: In /usr/local/share/FreeMat-4.0/toolbox/io/input.m(input) at line 37 In /home/jarle/freemat/inndata.m(inndata)… Read more
Here is my current method. Please let me know if you have a better one. The input data may be either space, tab, or comma delimited. ########################################################################## import os import re from numpy import array,zeros,concatenate,linspace,std from sys import stdin import matplotlib.pyplot as plt ######################################################################## def… Read more