Aerospace Vibration And Shock Testing

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

• 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
• 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

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

• Shock testing machines; limitations
• Use of shaker

Witnessing of tests

Course summary; optional final examination; award of certificates