Test Your Knowledge on Vibration Testing With This Quiz

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      Question 1
      What is an accelerometer's sensitivity defined in?

      1. pC
      2. pC/gn
      3. gn/mV
      4. gn

      Question 2
      What sweep rate will cause the most damage?

      1. 1 octave/min.
      2. 2 octave/min.
      3. 0.5 octave/min.

      Question 3
      The definition of random is:

      1. All the frequencies at the same time.
      2. At an instant in time you cannot define the level.
      3. A complex signal.
      4. White noise.

      Question 4
      The most commonly used crest factor used for random vibration testing is:

      1. 3.7
      2. 1.4
      3. 3.0

      Question 5
      The velocity a vibrator can achieve is proportional to:

      1. The current applied
      2. The armature mass
      3. The voltage applied

      Question 6
      One gravitational unit (gn) is exactly equal to:

      1. 9.80665 m/s²
      2. 9806.65 m/s
      3. 9.81 m/s²

      Question 7
      A vibration test system has a maximum sine force rating of 1500kgf peak and an armature mass of 23kg. A swept sine test is required as follows:
      10Hz to 700 Hz Acceleration = 15gn peak The Unit under test has a mass of 35kg and the fixture has a mass of 45kg.

      Can the system do the test?

      1. Yes
      2. No

      Question 8
      A random test using a crest factor of 2.3 is as follows:
      10Hz 0.4 gn²/Hz
      700Hz 0.4 gn²/Hz

      The total gnrms is:

      1. 12.77 gnrms
      2. 16.62 gnrms
      3. 5.78 gnrms

      The predicted displacement is:

      1. 21.79 mm peak to peak
      2. 6.61 mm peak to peak
      3. 16.71 mm peak to peak

      Question 9
      When a Vibrator's axis is changed from a vertical axis to a horizontal axis or from a horizontal axis to a vertical axis, what must be fitted?

      1. A warning label
      2. The lock out bolts
      3. An accelerometer

      Question 10
      A swept sine test has an acceleration target of 5gn peak, and the abort level is set to ±3dB. At what maximum acceleration would the test abort?

      1. 9.98gn
      2. 7.06gn
      3. 2.54gn

      Question 11
      A swept sine test goes from 12Hz to 550Hz (one unidirectional sweep). If the sweep from 12Hz to 550Hz should take 5 minutes, what is the log sweep rate?

      1. 2.2 octaves/min.
      2. 1.1 octaves/min.
      3. 1.1 Hz/s
      4. 1 dB/octave

      Question 12
      When using a sliptable, the control accelerometer should be fitted to:

      1. The driver bar
      2. The top of the armature
      3. The end of the sliptable
      4. The body of the vibrator

      Question 13
      A fixed frequency test is at 23Hz and the acceleration is 100m/s². What is the displacement?

      1. 9.57mm peak to peak
      2. 93.92mm peak to peak
      3. 0.035 in peak to peak
      4. 691.97 mm/s

      Question 14
      A vibrator has a displacement limit of 50.8 mm peak to peak and the test load is 100kg and the armature mass is 12kg and the body mass is 616kg. What is the maximum displacement that can be achieved if the body of the vibrator is isolated?

      1. 50.8 mm peak to peak
      2. 25.4 mm peak
      3. 8 mm peak to peak
      4. 44 mm peak to peak
      5. 52 mm peak to peak

      Vibration Test Engineer' Tool Kit will help you with the answers or e-mail richard.baker@vibkit.com

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