Why Vibration Tests Fail to Launch

Shakers, Vibration Control

Ready.  Set.  ARRGH!!

You are running a mission critical vibration test on a very expensive piece of equipment.  Weeks of preparation have gone into this one moment — one flip of the switch — and hopefully a successful outcome.  The countdown begins:

“In 3… 2… 1… Blastoff!

Umm… Blastoff…?

I said Blastoff, ARRGH!”

Testing:  Hollywood Style

At one time or another we’ve all seen a Hollywood portrayal of the inside of a command center moments before an important launch.

Scientists dressed in white darting about – Check

Countdown plastered on the largest screen in the room – Check

Fluid Levels correct – Check

Thrusters operational – Check

Gorgeous wives crying – Check

Doors secured – Check

That’s a typical launch – movie style!  The scene is always hectic and pressure packed.  One tiny mistake can destroy lift-off and if that happens, humanity will certainly be eradicated by the asteroid barreling toward earth!

Testing: Vibration Style

A similar sequence of events plays out on a daily basis in vibration laboratories around the world (minus the crying women and giant flashing countdown).  The scene is hectic and often the stakes are high.

Cables connected – Check

1.21 gigawatts on the input – Check

Amplifier gain turned up – Check

Careful preparation is a must whether you are getting ready to launch a rocket into space or getting ready to run a Sine test on your product.  The stress level can be quite high when working with million dollar prototypes or one of a kind test items.  There have been countless high-profile horror stories of these types of items being damaged or destroyed during a vibration test – often due to operator error or oversight.  Careless and costly mistakes can certainly stress-out vibration lab technicians and give them good reason to feel insecure about their future employment.

Stock Photo MathematiciansFeeling Stressed:  Shake it off by checking it off!

A vibration testing system has many components – the shaker, the amplifier, the accelerometers, the cables, the charge barrels, the computer, the chamber, to name a few.  Each test requires significant setup. Vibration lab technicians must be studious in this process or they may cause significant and irreparable damage to the product and their company.  Each step must be completed every time and it must be completed correctly.

There is nothing worse than going through a complex set of procedures only to realize that somewhere along the way one was missed, causing the end result to be failure.  It is like following a recipe for a loaf of bread and forgetting to add the yeast.  Even though all of the other ingredients are present in their correct quantities, the end result of forgetting the yeast is a flat, dense ball of inedible dough.  In vibration testing, every correct step can be tainted because of one misstep, such as:

  •          Forgetting to turn up the amplifier gain;
  •          Forgetting to check that the transducer sensitivity is set correctly;  or
  •          Forgetting to turn on the controller

If you approach your vibration test set-up half-hearted, the following may be your reality:

You take a seat at the computer and feel confident that clicking the ‘start’ button will certainly bring to life all of the equipment and the vibration test will go off without a hitch… *click*

ARRRGH! 

Nothing happens…

What’s the problem? 

It could be one tiny setback or it could be a major issue but the only way to know for sure is to begin the entire preparation process again.

Improper or lazy setup can lead to these types of intense, disappointing, and fearful moments.  Vibration Research never wants you to feel this ugly range of emotions.  We’ve created a vibration test set-up checklist just to be sure!  It can be used to ensure correct test setup every time and hopefully secure many successful lift-offs!

Print it!

Use it!

Keep your job!

Test Setup Checklist

 

Date

February 7, 2018

Author

jared

Category

Shakers, Vibration Control

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