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Re: [adatesman] Pull Test Results: Death and Dismemberment of Red Alien
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majid_sabet


May 2, 2008, 4:06 PM
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Re: [adatesman] Pull Test Results: Death and Dismemberment of Red Alien
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What is up with using the word "death" on every test ?l


zeke_sf


May 2, 2008, 8:11 PM
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Re: [majid_sabet] Pull Test Results: Death and Dismemberment of Red Alien [In reply to]
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majid_sabet wrote:
What is up with using the word "death" on every test ?l

Yeah, that's Majid's word!


mojomonkey


May 2, 2008, 9:39 PM
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Re: [adatesman] Pull Test Results: Death and Dismemberment of Red Alien [In reply to]
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So its too late to change my mind then, eh?


salamanizer


May 2, 2008, 11:20 PM
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Re: [adatesman] Pull Test Results: Death and Dismemberment of Red Alien [In reply to]
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Check out this piece of fixed mank I pulled out of Zodiac on the Captain about a month ago.
Don't know the story, nor do I really care. No question, the braze is the weak link in the Alien chain. Pulled it while standing on a black Alien above a string of copperheads. Bomber... Love my Aliens.

Anyway, thought I would share the pic cuz I thought it was funny/ironic. If you'll notice the stamped (tested) on the stem.Laugh

It's a black/blue hybrid BTW...


adatesman


May 3, 2008, 7:46 PM
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basilisk


May 4, 2008, 10:00 AM
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Re: [adatesman] Pull Test Results: Death and Dismemberment of Red Alien [In reply to]
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That it would fail below the braze isn't surprising. It's pretty standard that the weld is stronger than the materials. If you look at any welded piece of metal the weakest part is on either side of the weld. In this case there's only one side, so it stands to reason that it would break there.


blondgecko
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May 4, 2008, 6:11 PM
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Re: [adatesman] Pull Test Results: Death and Dismemberment of Red Alien [In reply to]
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adatesman wrote:

A chart of the load vs time.


I have to say, this chart disturbs me a little. It looks to me like there are a whole lot of little yielding events (slippage? breakage?) starting at less than 500 lbf. Really makes me wonder what a hysteresis test would show up. In other words, try cycling back and forth between 500 and 1000 lbf a few dozen times, and see if the curve at the end overlays with the one at the beginning - and if the ultimate strength of the cam is affected.


adatesman


May 4, 2008, 7:00 PM
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blondgecko
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May 4, 2008, 7:20 PM
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Re: [adatesman] Pull Test Results: Death and Dismemberment of Red Alien [In reply to]
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adatesman wrote:
Ah. wondering if anyone would notice that.... What you're seeing is evidence of the leaky seals on the pump and pullback ram. Wouldn't bug me so much if it weren't for the slowly growing oil stain under the puller. If I keep a small amount of pressure on the pump handle the seals hold fine, but the moment I ease off (like when pulling up on the lever for the next stroke on the pump) they leak a bit and the load starts dropping.

Stuff at Harbor Freight is cheap, but there's a reason for it.... Unsure

As for the little deviations between Live and Peak between the cycling of the pump, they come from the Peak channel scanning at 1000 samples/sec internal on the strain gage indicator and the live channel logging at ~8 or so samples/sec on the external datalogger. If I can get the serial connection to the datalogger running faster the discrepancy will get smaller, but so far no luck with that.

-a

Oh, here's a enlargement of the chart that shows it more clearly. The Live and Peak are pretty much identical except for during the cycling of the pump.

[image]http://www.shariconglobal.com/misc/pulltesting/red_alien/red_alien_chart2.JPG[/image]

Ok, so it's the rig and not the cam? That's a good thing.


bigo


May 5, 2008, 6:52 AM
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A load vs displacement graph would be more appropriate for identifying linear and nonlinear material behavior. Maybe invest in an extensometer.


notapplicable


Aug 15, 2010, 4:23 PM
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Re: [bigo] Pull Test Results: Death and Dismemberment of Red Alien [In reply to]
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PDF of google cached thread containing posts deleted by Aric.

http://www.keepandshare.com/...7-21-pm-1-2-meg?da=y


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