Consider a single-degree-of-freedom (SDOF) system subjected to base excitation. There are certain cases where the response of a system is known, but the base input acceleration is unknown. An example would be a seismic sensor which behaved as an SDOF system. The seismometer data would… Read more
Introduction Neither shock nor vibration response should be used to cover rigid-body acceleration because material limits depend on the strain rate and on the duration of the load. Furthermore, static deflection shapes differ from dynamic mode shapes. Material Stress Limits The following is an excerpt… Read more
The most widely used algorithm for the Shock Response Spectrum (SRS) calculation for base excitation is the ramp invariant digital recursive filtering relationship given in: David O. Smallwood, An Improved Recursive Formula for Calculating Shock Response Spectra, Shock and Vibration Bulletin, No. 51, May 1981.… 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
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