Optomechanics – An Engineer’s Tactile Sense

Colleagues:

It’s 2016 so, here we go….

For starters, I moved the AEH offices again.  See the new contact info below. 

Now, I’ve told you the story about the number of rivets in the Queen Mary.  Well here’s one about my calibrated thumb.

Early in my career my boss, Wilford, invited me to the environmental test laboratory.  We found a space payload mounted on the shake table.  He turned to me and asked, “What’s the fundamental resonant frequency of this beast?”  I turned to go up to the Structures Department but Wilford called me back.  He said something like, “We’re the mechanical engineers and should be able to get a pretty good handle on this right here.”

Wilford asked me, “How much do you think it weighs?”  I estimated the dimensions, studied the construction and made a guess.  He raised an eyebrow, but nodded.

Then Wilford walked around the payload and pressed on it several places then beckoned me over suggesting I press on it, which I did.  He asked how much it had moved.  I hadn’t noticed the motion so I pressed again and told him how much motion I had observed.  He asked how hard I had pressed but I had no idea.  He took me to the Inspection Department and had me push on the scales with the same force I’d pushed on the payload.

We went back to Wilford’s office and on his whiteboard he wrote “2 x pi x f = (k/m)^.5,” “k = force/motion” and “m = weight/gravity.”

The next day the test engineer reported that Wilford’s resonant frequency estimate, f, was 3% high.  Not bad.

My estimate wasn’t as good as his but I learned a lesson:  It’s useful for an engineer to maintain a tactile sense of the magnitudes of forces.  I cater to my right thumb.  What about you?

One more tool to keep sharp in 2016.

As I said up-top… “Here we gooooooooo!”

Al H.
1-5-16

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