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Fatigue test of D-shackles 1
- Thread starter tech20
- Start date
Hi
You will need a fatigue testing machine do you have access to one?
It might be cheaper just to buy some from here:-
You will need a fatigue testing machine do you have access to one?
It might be cheaper just to buy some from here:-
- Thread starter
- #3
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1
- #6
tech20,
In India, you may contact Central Mechanical Engineering Research Institute or Central Machining Testing .
It will be easier to buy certified D shackles, rather than attempting to get the test performed.
I followed this route, by bringing them from UK, they were cheap.
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
In India, you may contact Central Mechanical Engineering Research Institute or Central Machining Testing .
It will be easier to buy certified D shackles, rather than attempting to get the test performed.
I followed this route, by bringing them from UK, they were cheap.
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
- Thread starter
- #7
Tech20:
I suspect someone has done some fatigue testing on this type of equipment, but fatigue is really not the standard design philosophy for this equipment. These pieces of equipment are generally fairly conservatively designed and made by reputable manufacturers, and they are made with a factor of safety of 4 or 5 to ultimate strength or breaking strength. They are regularly proof tested to 1.25, 1.5 or 2 (or more) times their working loads. And, the thinking behind this is that the abuse they take in daily use is the real problem, rather than some fatigue issue being the problem. The dings or damage they might get in daily use causes stress raisers, or wear, or significant yielding and deformation which make them susceptible to failure. Finally, all lifting and material handling standards instruct that the equipment should be inspected regularly, maybe daily and before every significant lift for any damage or defects which might degrade their strength. Thus, fatigue is not likely the issue or the right question or criteria.
I suspect someone has done some fatigue testing on this type of equipment, but fatigue is really not the standard design philosophy for this equipment. These pieces of equipment are generally fairly conservatively designed and made by reputable manufacturers, and they are made with a factor of safety of 4 or 5 to ultimate strength or breaking strength. They are regularly proof tested to 1.25, 1.5 or 2 (or more) times their working loads. And, the thinking behind this is that the abuse they take in daily use is the real problem, rather than some fatigue issue being the problem. The dings or damage they might get in daily use causes stress raisers, or wear, or significant yielding and deformation which make them susceptible to failure. Finally, all lifting and material handling standards instruct that the equipment should be inspected regularly, maybe daily and before every significant lift for any damage or defects which might degrade their strength. Thus, fatigue is not likely the issue or the right question or criteria.
do you have a specific service load spectrum ? maybe 100,000 cycles of 75% proof load ??
would you plan on recurrent proof load testing (as outlined above) to say 200% proof ? if so this should be part of your fatigue spectrum.
if the shackle has been fatigue tested they'll have assumed a spectrum load and they may have included proof tsting (or not, conservatively).
"fatigue testing" is not a box that can be ticked. maybe your service loading is less intense than the OEM's assumptions. maybe you won't be proof loading ??
Quando Omni Flunkus Moritati
would you plan on recurrent proof load testing (as outlined above) to say 200% proof ? if so this should be part of your fatigue spectrum.
if the shackle has been fatigue tested they'll have assumed a spectrum load and they may have included proof tsting (or not, conservatively).
"fatigue testing" is not a box that can be ticked. maybe your service loading is less intense than the OEM's assumptions. maybe you won't be proof loading ??
Quando Omni Flunkus Moritati
A fatigue test conducted on one or two specimens is not meaningful on its own. What matters is whether the production parts are produced with similar characteristics as the test articles had. Components that are required to meet certain strength and quality requirements usually come with a Certificate of Conformance (C of C) that shows the components were manufactured, inspected and tested in compliance with contract specifications.
If you were to send a pair of shackles out for fatigue testing, all that would prove is that those two shackles had a certain fatigue life given the test load conditions.
If you were to send a pair of shackles out for fatigue testing, all that would prove is that those two shackles had a certain fatigue life given the test load conditions.
Fatigue testing was not done for my procurement. However as Tbuelna mentioned a safety factor of 1.25 of working load was verified. This test was confirmed by a 3rd party inspection agency like B.V .It was Oil and Gas industry HSE requirement.
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
I'm just one step away from being rich, all I need now is money.
( read somewhere on the internet)
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