Vibration Research Corporation

www.vibrationresearch.com

NEW!! iDOF: instant Degrees Of Freedom - Prevent Under or Over Testing

  • Instant equalization for high level, short duration tests
  • Achieves tight tolerance Random control resetting averaging during during level changes, eg. (MIL-STD 1540)
  • Actual data displayed at all times -- does not hide or gloss over potentially damaging resonances by forcing a smooth PSD 
  • Achieves prescribed statistical degrees of freedom based on industry-leading lines of resolution and Dual High-Speed RISC processing power
  • Facilitates decisions on under/over test conditions

Direct Link https://www.youtube.com/watch?v=J5twmtsmG40

Please see the video just released by Vibration Research

Fatigue Damage Spectrum (FDS) - Excitation severity in terms of cumulative damage

  • Eliminates shortcomings of PSD and gRMS -- invalid for Non-Gaussian and non-stationary
  • Multiple time Histories—Import, weight & combine. Long enough for Kurtosis to develop
  • Generate PSD of equivalent damage
  • Re-introduce Kurtosion based on Actual EUE peaks, NOT previous kurtosis of imported time histories because gRMS is changed due to compressing the test.
  • Comparison of specs. EUE, shakers, “m” and Q, Sensitivity analysis
  • By spectrum and ? for both broadband and narrowband -- ½ power bandwidth for product resonance responses
  • “One test fits all”—group and rank by ?DAM, generate FDS for groups
  • ?DAM for 3 axis damage —ED, and RS/HALT machines—Arithmetic, not vector sum
  • Loses Ordering of stress cycles as with PSD
  • Quantitative Comparisons-
  • Avg/Peak hold PSDs with FDR
  • PSD damage with & without Kurtosion

Kurtosion-Statistically More Accurate Random Testing

  • Random with PDF ModificationKurtosion Ppd
  • Introduce Field (EUE) peaks
  • Patented Metric impulse method, ½ power bandwidths—not distortion
  • Proof-check PDF of response channels
  • PSD and gRMS unchanged because overlapped and ensemble-averaged FFTs don’t accommodate non-Gaussian peaks
  • Specs-better representation of severity
  • Loses ordering of stress cycles as does PSD
  • Trade-off-Kurtosion vs. increasing RMS to get peaks > 4-5 ?—over-powered

To view articles on our patented KurtosionTM control check out VR's “Published Articles” page. Read our most recent publication on Using Kurtosion® to Accelerate Structural Life Testing.

Field Data Replication

  • 1:1 Replication
  • 20 imported time histories-Edit & Schedule
  • 3rd control loop of phase
  • Buffered demand allows unlimited duration and sample rate
    Example:
      • Engine Run-up
      • Introduction of transients
      • Introduction of sine tones
      • Maintains order of stress Cycles
      • Cannot be accelerated and maintain advantages

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