Self-equilibrating stress
Self-equilibrating stress
(OP)
Can anyone explain to me what a "self-equilibrating stress" is? I heard this term used in reference to bolt preload. Something to the effect that preload is a self-equilibrating stress, and therefore is a secondary stress which can be subtracted from the total stress before the safety factor is calculated.





RE: Self-equilibrating stress
Mike Halloran
Pembroke Pines, FL, USA
RE: Self-equilibrating stress
I know this is a simplification, and that other ways of analyzing preloaded bolts are out there. So when I heard the idea that I explained in my original post, I thought it might just be a different way of looking at things. I probably misunderstood though.
RE: Self-equilibrating stress
I cannot quite agree with your analogy, my understanding is that if the external load exceeds the bolt preload, then the joint will separate and the bolt takes all the external force but up to that point any external load is shared between the clamped components and the bolt proportional to the stiffness of the clamped components and that of the bolt.
Now the clamped parts are normally much stiffer than the bolt itself so what happens with an external load below the preload value is that it reduces the compressive stress between the clamped faces but however increases slightly the tensile stress in the bolt, all this is nessecary to maintain equilibrium.
Please see bolt joint diagrams on this link
http://www.roymech.co.uk/Useful_Tables/Screws/Prel...
“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein