Synthesizing a Half-Sine Pulse to Satisfy an SRS

Testing to Shock Response Spectrum (SRS) specifications is usually performed using complex oscillating waveforms.  This is also true for analytical simulation  in the time domain. There are several reasons for this. Complex oscillating pulses can typically meet both the positive and negative SRS for a… Read more

Fatigue Damage Spectrum, Time Domain

Consider a single-degree-of-freedom system subjected to base excitation where the input is an arbitrary time history. The response of the system can be calculated via a digital recursive filtering relationship, which is the numerical engine embedded in the SRS calculation.   This is done for… Read more

Vibrationdata Matlab Signal Analysis & Structural Dynamics Package

Please send me an Email if you are going to use this package. Also, you are welcome to participate in the Shock & Vibration courses. Thank you,Tom IrvineEmail: tom@irvinemail.org * * * License information: The software packages on the following links are freely placed in… Read more

David O. Smallwood Papers

David O. Smallwood, An Improved Recursive Formula for Calculating Shock Response Spectra, Shock and Vibration Bulletin, No. 51, May 1981.  DS_SRS1.pdf Time History Synthesis for Shock Testing on Shakers: th_syn.pdf The Shock Response Spectrum at Low Frequencies: low_srs.pdf A Family of Transients Suitable for Reproduction… Read more

SRS Educational Animation

The following animation file is useful for demonstrating the Shock Response Spectrum (SRS) concept : HS_SRS.avi & Alternate Link Each system is subjected to a common base input which is a 1 G, 1 second half-sine pulse. Each system has an amplification factor of Q=10.… Read more

MIL-S-901 Medium Weight Shock Test Machine

Occasionally I receive questions regarding the equivalent SRS for a MIL-S-901 shock test.  Alas, I have no experience with MIL-S-901 testing. But a “MIL-S-901 Medium Weight Shock Test” SRS plot is given on page 45 of the following document: Gaberson, Pseudo Velocity Shock Analysis, Shock Severity… Read more

Dr. Howard Gaberson’s Papers

Howard A. Gaberson (1931-2013) was a shock and vibration specialist with more than 45 years of dynamics experience.  He was with the U.S. Navy Civil Engineering Laboratory and later the Facilities Engineering Service Center from 1968 to 2000, mostly conducting dynamics research. Gaberson specialized in… Read more

Stress-Velocity Relationship

Shock and vibration environments produce dynamic stresses which can cause material failure in structures. The potential failure modes include fatigue, yielding, and ultimate stress limit. F.V. Hunt wrote a seminal paper on this subject, titled “Stress and Stress Limits on the Attainable Velocity in Mechanical… Read more