New Shepard Launch I have been working at Blue Origin in Kent, WA since February 2019. This is an excellent work environment with engaging technical opportunities. Blue Origin is hiring engineers including some for vibroacoustics. Please see: https://www.blueorigin.com/careers Applicants must be a U.S. citizen or permanent… Read more
Consider the case where flight or test pyrotechnic source shock data has been measured on a launch vehicle with a 1-meter diameter aluminum cylindrical shell. Assume that the source device is frangible joint with a certain number of grains per length. Now the same device… Read more
This is a work-in-progress. Here are some slide presentation with an emphasis on launch vehicles. Equivalent Static Loads for Random Vibration & Alternate Link Damping & Isolation & Alternate Link Liftoff Vibroacoustics & Alternate Link Ascent Vibroacoustics & Alternate Link Launch Vehicle Pogo, Combustion Instability… Read more
Structural dynamics systems can be represented in terms of mass, damping and stiffness matrices. Each of these matrices may be coupled depending on the model complexity, degrees-of-freedom, etc. The mass and stiffness matrices in the assembled equation of motion may be uncoupled using the normal… Read more
Structural system & component damping can measured via modal testing with applied force excitation. One excitation method is an impulse hammer test. Another method is a small shaker attached to structure via a stinger rod. Damping can also be measured by mounting the test unit… Read more
Structural damping depends on materials, joints, boundary conditions, friction, acoustic radiation, etc. Damping may be nonlinear, increasing as the excitation and response levels rise. The damping for a given structure or component must be measured! But here is some empirical background data… Papers Damping Properties of… Read more
For the past eight years, I have written a required monthly status report to another organization for my NASA contractor work. I have written my accomplishments and planned work in short, concise sentences, usually in numbered list format. I was then notified by this organization… Read more
Honeycomb sandwich structures are designed to have a high stiffness-to-mass ratio. The stiff, strong face sheets carry the bending loads, while the core resists shear loads. The face sheets are typically made from aluminum or carbon fiber with epoxy resin. The honeycomb core material is… Read more
Aerospace pyrotechnic shock response spectrum (SRS) specifications are almost always given with an amplification factor Q=10 Corresponding time history waveforms for the base input acceleration are almost never given with the specifications Users are allowed to synthesize their own waveforms to satisfy the SRS for… Read more
Shock and vibration analysis can be performed either in the frequency or time domain The time domain method requires more computation time but is much better suited for transient and nonstationary excitation Time domain methods are also better for rainflow fatigue cycle counting Students should… Read more