Multiaxis Fatigue

Here is a preliminary version of a paper that I am going to present at conference in the UK, July 26.  Multiaxis Rainflow Fatigue Methods for Nonstationary Vibration. Extended Slides:  Irvine_multiaxis_fatigue.pptx Abbreviated Conference Slides:  Irvine_multiaxis_fatigue_RASD_revA.pptx The conference is:  MOVIC & RASD 2016 See also: Rainflow Cycle Counting In-plane Rectangular Plate… Read more

In-plane Rectangular Plate Vibration, FEA

I have written a function for calculating the natural frequencies and modes shapes of a rectangular plate undergoing in-plane vibration via the finite element method. The function is included in the software posted at in the Matlab GUI package. The function can be accessed via:… Read more

Kinetic & Strain Energy Formulas

Kinetic & strain energy formulas can be used as a basis for Rayleigh-Ritz or finite element analysis of vibrating structures. Equations for common structures and loading conditions are given in strain_energy.pdf The cases include: Uniform Bar under a Constant Axial Load Bar under a General Axial… Read more

Vibroacoustics/Statistical Energy Analysis

Like Robert Frost, I have miles to go before I sleep, and all because I took the road less traveled… This is a long-term work-in-progress… I am including SEA in my Matlab GUI package. The functions can be accessed via: vibrationdata > Miscellaneous Functions I… Read more

Payload Fairing Foam Blankets

A spacecraft at launch is subjected to a harsh acoustic and vibration environment resulting from the passage of acoustic energy, created during the liftoff of a launch vehicle, through the vehicle’s payload fairing. In order to ensure the mission success of the spacecraft it is… Read more

Adding Uncertainty Margin

One of my colleagues asked whether uncertainty margin should be added to the input or the response, particularly for a nonlinear system.  I recommend adding to the response.  He asked that I write a paper using an acceleration base input which he supplied.  The results… Read more

NASA Employment Opportunity

From a colleague… I just wanted to let you know that we would have a GS-13 posting out next week seeking for an experienced strength/fracture engineer to fill a vacant position in my branch here at LSP.  I would appreciate very much if you can… Read more

Employment Opportunity

Here is a job opening in Huntsville, Alabama for helicopter air frame finite element analysis: http://www.avnikdefense.com/index.php/careers/current-openings/9-available-positions/37-mid-level-mechanical-engineer-structural-analyst I spoke with the CEO, Michele Kochoff Platt.  This is an excellent opportunity.  So please forward this link to any of your colleagues who are seeking employment.  Note that… Read more

Some Vibration Testing Q & A

Here are some questions from students that I recently received for shaker table testing of equipment. How are vibration standards developed and how do they relate to the operational environment? Standards may have different purposes.  Some of the common ones are: Envelope the actual field… Read more