Basic series in Vibration and Acoustics
(6-hour DVD serie)
The DVD lectures "Basic series in Vibration and Acoustics" come in four DVDs. The DVDs include a copy of a program transmitted via satellite in December 1997, featuring Wayne Tustin.
We thank National Technological University, Fort Collins, Colorado for the use of this material.
Cost: US$ 750 + shipping
Click here to purchase the 6-hour DVD serie
Course Outline
Hour 1
- Introduction to the course
- Purposes and types of environmental tests, emphasizing vibration and shock
- Introduction to classical sinusoidal vibration and sound
- Unidirectional (automobile) displacement, velocity, acceleration
- Sine vibration: displacement, velocity, acceleration
- Single-degree-of-freedom system, natural frequency
- Transmissibility, resonance, isolation
- Single-degree-of-freedom demonstration on shaker
- Critical damping: Army gun recoil demonstration
- Passive vs. active isolation
- Cantilever beam demonstration on shaker
- Natural frequencies of a cable under tension, musical instruments, classical beams and plates
- Modal analysis and testing
- Effect of damping
Hour 2
- Sinusoidal vibration and sound measurements
- Linearity; probability
- Instruments: sensors especially accelerometers, force sensors, microphones
- Readouts; sources of error; six ratios between force and motion
- Calibration of sensors and systems; NIST traceability
- Absolute vs. comparison
- Calibration at various temperatures
- Microphone calibration
- Most machinery vibration is complex; introduction to spectrum analysis
- Time and frequency domains; Fourier transform
- Multiple frequencies; spectrum analysis; line spectra
- Videotaped demonstration: sine and square waves; musical tones
Hour 3
- An early military test specification
- Examples of sinusoidal vibration calculations
- Better understanding resonance
- Stiffness/natural frequency relationship
- More on instrumentation, spectrum analysis, avoiding measurement errors
Hour 4
- Review of first day; preview of today
- What should we test? When should we test it? Where should we test it?
- Vibrating platforms; need for multiple exciters; mechanical shakers not too useful
- Electrohydraulic shaker systems; multi-axis testing more realistic than single axis
- Electrodynamic shaker systems
- Unwanted shaker motions
- Multi-axis electrodynamic shaker systems; video clip
- Modal analysis; modal testing with electrodynamic shakers
- Power amplifiers; current and voltage demand; harmonic distortion effects on shaker
- Electrodynamic shaker system ratings
- Understanding sinusoidal vibration test specifications
- Why are we still doing sine tests?
- Shaker controls: older analog and present digital shaker controls
- Load resonances; antiresonances
- Sine vibration testing; control strategies
Hour 5
- What is random vibration?
- Review of line spectra; extend to continuous spectra
- Sources (in service) of random vibration
- Random vibration video clip
- No equivalence between random-sine
- Instrumentation for random vibration; narrow-band spectrum analysis; need for g2/Hz
- Meaning of term RMS
- Earthquakes are random
- Designers: don't stack your resonances!
- Amplitude sampling; probability density graphs
- DeciBel notation in random vibration testing
- Fitting test spectra to field data
- Older analog spectrum shapers reviewed; today's computer controls Introducing Gerry Priebe of Data Physics Corp.
- Sine signal demonstration; waveform and histogram
- Random signal demonstration; waveform and histogram
- Sine and random mixed signals; waveform and histogram
- Tiny shaker - random vibration demonstration; beams with accelerometers
- Computer compensates for resonance characteristics of shaker and of load
- Repeat for swept sine test; mention of sine on random testing, force limiting
Hour 6
- Vibration test fixtures; function of fixture; classical fixtures types
- Attempt to keep fixture resonances above the test frequency range
- Fixture fabrication - most often welded
- Bolted connections - axial loading - lateral loading
- Mechanical impedance of fixtures; attempt to match service mounting
- Avoid fixtures overhanging shaker table; us of head expanders, slip plates
- IEST Recommended Practices on Fixture Design
- Environmental stress screening (ESS) and related topics
- Thermal stressing
- Random vibration stressing; multiple-axis excitation with pneumatic vibrators
- Ford video clip
- Buzz, squeak and rattle (BSR) problems explained; solutions
- BSR vibration testing
- HASS, HASA, HALT testing; compressing test time
