V$S 520 – Fundamentals of Vibration and Shock Testing of Military COTS/NDE (Commercial Off The Shelf, Non-Developmental Equipment) hardware

Overview for management and participants

  • Purpose of environmental testing, particularly vibration and shock
  • Purposes of HALT, ESS and HASS
  • Extensions to HALT (highly accelerated life testing) and to HASS
  • Types of vibration tests: resonance search/dwell, fatigue, specification
  • Approximate scheduling so managers can audit special topics

Quiz for evaluation of attendee prior knowledge

Classical sinusoidal vibration never observed in service; useful concept

  • Introduction: terminology, structural resonant behavior
  • Passive and active isolation, as in protecting against battlefield environment
  • Sinusoidal vibration measurements: units, sensors, readouts, errors
  • Calibration of sensors and systems; traceability to NIST

Most machinery vibration is complex; introduction to spectrum analysis

Sinusoidal vibration testing

  • Electrohydraulic and electrodynamic shakers; theory, tradeoffs, limits
  • Standards, controls, practice

Introduction to random vibration

  • Sources of random vibration in service and transportation
  • Terminology and definitions
  • Spectral density measurement and analysis – the frequency domain
  • Probability density – the time domain

Random vibration test practice

  • Interpreting and implementing standards, e.g. MIL-STD-810
  • Controls, practice

Combined environment (CERT) testing; reliability tests, e.g. MIL-STD-781

Environmental stress screening (ESS) of electronics hardware production; extensions to HALT and HASS

  • Single vs. multi-axis vibration
  • Pneumatic repetitive-shock machines

Vibration and shock test fixtures; fixtures for stress screening

  • Recommended designs, materials, fabrication methods
  • Experimental evaluation before use

Shock measurements in field and laboratory

Shock testing standards and methods

  • Shock testing machines; limitations
  • Use of shaker, shock response spectrum (SRS)

Design of new equipment to withstand vibration and shock

  • Do not stack resonances
  • Octave rule

Protecting commercial equipment against the battlefield environment

  • Thermal protection – cocooning
  • Vibration and shock protection – isolation

Witnessing of tests

Course summary; optional final examination; award of certificates

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