V&S 516 – Shipboard Vibration and Shock Testing, Measurement, Analysis and Calibration also HALT, ESS and HASS

Overview for management and participants

  • Purpose of environmental testing, particularly vibration and shock
  • Purpose of environmental stress screening (ESS)
  • 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
  • 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

  • Limitations of earlier mechanical shakers
  • Electrohydraulic and electrodynamic shakers; theory, tradeoffs, limits
  • Power amplifier theory, operation, limitations, distortion effects
  • Controls for sinusoidal vibration testing
  • Sinusoidal vibration test practice
    • Interpretation of standards; e.g. MIL-STD-810, MIL-S-167
    • Controversial test methodology: tracking filters, switching and averaging among sensors
  • Vibration and shock test fixtures; fixtures for stress screening
    • Recommended designs, materials, fabrication methods
    • Experimental evaluation before use
  • Practical limits: transverse motion; specimen size and weight

Introduction to random vibration

  • Sources of random vibration in service and transportation
  • No possible equivalence to sinusoidal vibration
  • 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
  • Equalization before testing; methods and limits
  • Controls
  • Electronic protection for test items and shaker system

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

Environmental stress screening (ESS) of electronics hardware production

  • Single vs. multi-axis vibration
  • Pneumatic repetitive-shock machines; HALT and HASS

Acoustical environment (intense noise) testing

Instrumentation for measuring shock in service and during tests

  • Sensors, readouts, errors
  • Calibration
  • Shock spectrum analysis; shock response spectrum

Shock testing standards and methods

  • 901 hammer machines; limitations; Newport machines
  • Ship and barge shock tests
  • Use of shaker for shock testing

Witnessing of tests

Course summary; optional final examination; award of certificates

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