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
