Spring Creep issue
Spring Creep issue
(OP)
I am struggling with trying to verify a new design. Here is most of the information:
I have a mineral insulated thermocouple cable that is coiled into a compression spring. It is being compressed slightly approx 2.25 lbs load.
The sheath material is Hastelloy X 0.063" dia. and it will be in an environment where the max temp could get up to 1200 F. Once installed the spring will be not be cycled.
I am just trying to figure out if the load/temperature will cause significant creep.
I want to complete this problem assuming a hollow tube as worst case scenario. I have calculated the stress in the spring but I have no information to calculate max allowable stress.
Although this should show if the spring is okay based on the load it does not take into account the temperature.
The temperature is what i am most worried about but cannot figure out a way to prove it will not cause creep in the spring.
Not sure if i am looking to deep into this but i need some kind of evidence/calculations to prove this out.
Any help would be appreciated.
Thank you
Ryan
I have a mineral insulated thermocouple cable that is coiled into a compression spring. It is being compressed slightly approx 2.25 lbs load.
The sheath material is Hastelloy X 0.063" dia. and it will be in an environment where the max temp could get up to 1200 F. Once installed the spring will be not be cycled.
I am just trying to figure out if the load/temperature will cause significant creep.
I want to complete this problem assuming a hollow tube as worst case scenario. I have calculated the stress in the spring but I have no information to calculate max allowable stress.
Although this should show if the spring is okay based on the load it does not take into account the temperature.
The temperature is what i am most worried about but cannot figure out a way to prove it will not cause creep in the spring.
Not sure if i am looking to deep into this but i need some kind of evidence/calculations to prove this out.
Any help would be appreciated.
Thank you
Ryan





RE: Spring Creep issue
RE: Spring Creep issue
The big question is how long the spring needs to produce useful force. This is basically what i am struggling to figure out. We need the force to stay close to the initial load for this design to work.
I cant find any equation that takes into account stress and temperature to tell you how this force will react over time. I would like to know how to calculate this so i can come up with a graph or some number of hours/days the force will start to taper off.
RE: Spring Creep issue
http://www.lesjoforsab.com/technical-information/t...
http://www.amspringwire.com/valvetechbulletin.pdf
http://materion.com/~/media/Files/PDFs/Alloy/Techn...
http://smihq.org/public/publications/07_47_04/_hot...
http://www.db-thueringen.de/servlets/DerivateServl...
RE: Spring Creep issue