Vibration and Shock Test Fixture Design
(FIXT 501)
Overview
- Purpose of environmental testing, particularly vibration and shock
- Types of vibration tests: resonance search/dwell, fatigue, specification
- Importance of fixtures for meaningful vibration and shock testing
Quiz for evaluation of attendee prior knowledge
Review of classical sinusoidal vibration never observed in service; useful concept
- Introduction: terminology, structural resonant behavior, isolation
- Sinusoidal vibration measurements: units, sensors, readouts, errors
- Short review of vibration and shock calibration
Review of complex vibration; introduction to spectrum analysis
Review of instrumentation for measuring vibration and shock in service and during tests
Review of 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
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
Review of random vibration test practice
- Interpreting and implementing standards, e.g. MIL-STD-810
- Shaker control; methods and limits
Review of shock testing standards and methods
Emphasis on vibration and shock test fixtures
Recommended designs
- Standard lab fixtures
- Special designs, customized mounting systems
Fixture materials
- Recommended materials
- Factors in determining appropriate materials
- Inserts and other specimen attachment techniques
Recommended fabrication methods
- Bolting, welding, casting, other
- Comparisons of methods
Experimental evaluation before use
- Purpose and requirement for fixture evaluations
- Methods of evaluations, pitfalls
Practical limits: transverse motion; specimen size and weight
Control accelerometer location determination
- Best practices
- Experimental processes
Course summary; award of certificates
