Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Search results for query: *

  1. floattuber

    Carbon Fiber vibration Fixture?

    Has anybody tried using carbon fiber as a fixture material? Here in the vibration lab, we were brainstorming about alternative fixtures for our products and an outside the box suggestion of carbon fiber came up. We're thinking why not? A foam core would be great for vibration damping, the...
  2. floattuber

    Why do a bare fixture eval?

    Ok thanks for validating my thoughts. Greg, the best response that I've heard so far is that bare fixture response is close enough to real test conditions and fixing any resonances in the region of interest is better than doing nothing.
  3. floattuber

    Why do a bare fixture eval?

    We run aerospace parts ranging in size from baseball size up to 1000 pound engines on our shakers. Some customers want to do a bare fixture evaluation and some don't. I've heard some reasons to do it and some reasons for why it's a waste of time but I haven't been able to really delve into it...
  4. floattuber

    Vibration Test Equipment

    Perhaps as a proof of concept, you can download an app for your phone that displays what the built in accelerometers measure. The operative word here is that it's free or at most, a couple dollars. Make sure you remove the phone from the case, first. I have a couple for my iphone, one is...
  5. floattuber

    Severance or relocate

    I used to live in the bay area and moved out of state because of the cost of housing. Can you afford to buy a house for $600,000-750,000? I moved away right before the economy went down, but at the time I could only afford 300k-400k, and we were only able to look at run down, 2 bedroom...
  6. floattuber

    Resonance dwell nomenclature

    StrikerTech, but once that resonant frequency is found and you dwell at it...what if the resonant frequency changes during the course of the dwell. Say it shifts 3% higher. Do you adjust the frequency on the fly to continuously track it, or do you stay at the original frequency? That's the...
  7. floattuber

    Resonance dwell nomenclature

    Thanks. I'm having a discussion with my tech about the definition of "Resonance Dwell". At this site, the conventional nomenclature of "Resonance Dwell" specifically means a tracked dwell (follow any frequency shifts) while "Fixed frequency" means stay with one frequency regardless of...
  8. floattuber

    Resonance dwell nomenclature

    What do the terms "resonance dwell" mean to you? Does it mean tracking dwell or fixed freqency dwell? Or is it more of a general term that further needs to be defined by "track" or "fixed"?
  9. floattuber

    Suggestions for Particle Counting Microscope?

    In addition to the microscope, they make software that does this automatically, however it's not cheap. The olympus microscopes that my previous company used were about $45,000 each plus the price of the basic software. Particle counting was extra. Have you thought about outsourcing this work...
  10. floattuber

    Flat washer direction

    No, we were using cheap COTS washers for a somewhat large piece of equipment, not fender washers. This was not an important application.
  11. floattuber

    Flat washer direction

    I've read that lock washer thread before but missed the one Mint linked. Our MS washers also don't have this problem. I didn't think it would matter considering the hundreds, thousands or tens of thousands of pounds of force that a bolt can produce. The only thing I could think of was that...
  12. floattuber

    Flat washer direction

    Maybe I missed this in the search, but I didn't see this topic posted before... Recently, one of the grey beards (or mustache in this case) said to always put a washer on a bolt a certain way. The washers are stamped so often times there is a curve or bow to them and they also have a slight...
  13. floattuber

    No promotions in place

    Well things just got interesting...I got promoted...in place. It was certainly a shock to me. After thanking the boss, I flatly asked about the "promote in place" policy and he said yeah all the managers are hounding the HR people about it and they are either giving up on the policy or are...
  14. floattuber

    Sine-on-Random - Clarification

    It depends. I've run one SOR where the levels of the tones were so small in comparison to the random level, that the tones either didn't show up or were barely noticable. Also, with our spectral dynamics software, we can choose for the tones to be additive or not. But yes, in general, the...
  15. floattuber

    Low freq shaker motion subtract from unit motion

    Thanks all, looks like I was right. We've done it both ways here, with the vast majority having the control accel(s) right next to the unit on the fixture. For the sake of this discussion, I just said "on the unit" for simplicity.
  16. floattuber

    Low freq shaker motion subtract from unit motion

    Mike - "The displacement of the UUT relative to the floor/ building/ local 'ground' is what's important." Greg - "But if the accel is on the UUT there is no problem." I think this is where I'm getting confused. Our control accel is on the unit. It seems to me that the displacement relative...
  17. floattuber

    Low freq shaker motion subtract from unit motion

    I've been told that at low frequencies, <3ish Hz, that the motion of the whole airbag supported shaker subtracts from the motion of the unit under test, but I'm having a hard time wrapping my head around it. For example, when we ran a dwell at 2 Hz the whole shaker moved, about 1/2", roughly...
  18. floattuber

    Machine shop over ran quote

    Their labor rate is indeed cheaper than the US shop rate, however, the SOTB shop takes twice as long! Ultimately, everybody who buys a plane ticket picks up the tab.
  19. floattuber

    Machine shop over ran quote

    I'm letting management sort it out. My managers agree, the shop should eat the cost, but I know that's not going to be the case. We'll end up having to pass the cost on to our internal customers.
  20. floattuber

    Machine shop over ran quote

    Thanks for the replies; they mirror my thinking and just about everybody else's here. Here's the fun story. I work for a large aerospace company and the machine shop is a group within the company but they are based in an "emerging market" south of the border (SOTB). They have to bid for our...

Part and Inventory Search

Back
Top