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… Read more
Here is a sample SRS specification. The ramp is a constant velocity line with slope = 6 dB/octave. SRS Q=10 fn(Hz) Peak Accel (G) 10 10 2000 2000 10000 2000 Here is a set of files which satisfy the SRS. ASCII text: srs2000G.zip The files… Read more
PowerPoint File: webinar_20_digital_filtering_part_2.pptx Audio Visual File NESC Academy Digital_Filtering_Part_2 – Recommend viewing in Firefox with Sliverlight plugin * * * PSD Data File: navmat_spec.psd * * * Python Version: webinar_20_digital_filtering_part_2_python.ppt Python script: Python Signal Analysis Package GUI * * * Reference Papers: An Introduction to the… Read more
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
Wayne Tustin is a pioneer in the field of shock and vibration training. I have had the opportunity to learn from him at several IEST meetings and other conferences. He taught me the meaning of SRS (G) and PSD (G^2/Hz) units, when I was… Read more
I recently flew as a passenger in a CRJ900 jet similar to the one shown in Figure 1. This aircraft has two GE CF34-8C5 engines, as shown in Figure 2. This engine has two high pressure axial flow stages that drive the N2 compressor, and… Read more
Update: Spacecraft On-Orbit Microvibration & Jitter Slides Introduction Spacecraft must withstand vibration from pre-launch transportation and from powered flight. The spacecraft is not powered during these events. In addition, a spacecraft must withstand “microvibration” or “jitter” from its own moving parts once it reaches orbit… Read more
We are not human beings having a spiritual experience; we are spiritual beings having a human experience. – Pierre Teilhard de Chardin (1881-1955) * * * Also quoted by: President Thomas S. Monson, BYU Devotional Be a Light to the World, November 1, 2011 *… Read more
PowerPoint File: webinar_19_digital_filtering.ppt Audio/Visual File: NESC Academy Digital Filtering – Recommend viewing in Firefox with Sliverlight plugin * * * Python version: webinar_19_digital_filtering_python.ppt Python script: Python Signal Analysis Package GUI * * * Data: sm.txt – unscaled relative displacement vs. time (sec) * * * Reference… Read more
Method 1 Secondary & Component loads can be specified in the form of a Mass-Acceleration curve as described in: NASA-STD-5002, Paragraphs 4.2.1.2, 5.3.2, 5.4. The Mass-Acceleration curve can be derived from measured flight or test data, or analytical loads. Care must be taken to avoid… Read more